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The blower resistor is located on the passenger side of the vehicle behind the glove box. There is a plastic cover that has to be removed to gain access to the resistor and wiring.
After the cover is removed disconnect the harness connector and inspect for damage. On this particular vehicle the only terminals that were damaged were the third from the right and the third from the left. Sometimes all of the terminals will be damaged and the plug will be melted to the resistor as shown in the last pictures.
After thoroughly inspecting the connector for damage the terminal retaining comb was removed from the old and the new harness connectors. The good wiring was transferred one at a time from the old connector to the new connector. A terminal extracting tool is needed to do this. The locking tab must be slightly depressed before the terminal can be removed from the connector. A solid piece of wire such as a larger paperclip could be used if a tool is not available. If you do not have an adequate tool or experience this should not be done. Cut the wires one at a time and splice in to the harness using a quality butt connector.
Be sure to stagger the spliced connectors as much as possible in order to have a neater and less troublesome repair.
Retape the harness and install the new blower resistor and harness connector. As with any wiring repair that involves a burnt connector, the connector and the component that it attaches to must be replaced at the same time or the repair will fail very quickly.
This connector like many that will be found was melted to the resistor and every wire had to be replaced. You can save yourself time and money by always being aware of changes in your vehicle and repairing them as soon as possible. If you need quality parts click here.
I recently completed a video on this repair as well. Please click here to view.
I am adding testing instructions due to popular demand. Testing is as follows. Disconnect the 7 wire harness connector and inspect. If there is any sign of heat damage replace both parts per above instructions. If there is no sign of heat damage then check the following. With the 7 wire harness disconnected check for power on the red wire. It should have 12 volts at all times and it gets it's power from the 40 amp blower fuse in the under hood fuse box. Next with the key on check for 12 volt power to each of the following wires as you move the blower speed switch from low to high. Yellow / low, tan / med 1, lt blue / med 2, purple / med 3 and orange / high. Remember, this test is done with the key on and the seven wire harness disconnected. Other than the red wire having power at all times, only one wire at a time will have power on it, during a proper test. If there is no power to any of these wires during the test , check the fuse in the driver's interior fuse box. If only some of these signals are missing, you will need to inspect the blower speed switch and related wiring. Also you should do a drag test on the terminals to check the spring tension. Please click here for more instructions
- Terminal "A" Tan = Speed 2, power through blower switch from HVAC fuse
- Terminal "B" Yellow = Speed 1, power through blower switch from HVAC fuse
- Terminal "C" Purple = Speed 4, power through blower switch from HVAC fuse
- Terminal "D" Lt Blue = Speed 3, power through blower switch from HVAC fuse
- Terminal "E" Black = Blower system, ground at all times
- Terminal "F" Orange = Speed 5, power through blower switch from HVAC fuse
- Terminal "G" Red = Speed 5, Constant power from BLWR fuse under hood
If all of the tests above are okay and you want to go a step further, place a test light or voltmeter in the wires going to the blower motor. If the light comes on or you have a 12 volt reading, the resistor and wiring are okay and the blower motor is faulty. This can also sometimes be confirmed by bumping the blower motor with the switches on. If the motor starts after bumping the motor is faulty. One can also remove the blower motor and apply 12 volts (power and ground) directly to the motor. Be careful though the motor will tend to jump and roll all over the place. Hold it firmly and be sure you are clear of the impeller as it could hurt you pretty easily.
One other note. If you have an amperage gauge, test the blower amperage draw while it is mounted in the blower case. Turn on surge amperage could go up to about 28 amps. Amperage draw at high blower should be in the 18 to 24 amp range. The lower the better. Restricted cabin air filters (if present) and dirty evaporator cores will cause a blower motor to draw more current while reducing air flow volume. These two conditions combined will significantly reduce the life of any blower resistor.
More additions to make parts identification hopefully easier. The following picture is of a floor mounted center console. In ordering, this is one of the most important features that we need to know about your truck. Please be sure to leave this information along with year, make, model, engine size, type of cab (regular, extended or four door) and confirmation that you have manual a/c. Leave this info in the customer comments box at check out when ordering. You may also email us anytime or call us 8:00 am to 6:00pm EST
The following picture is of an original two piece blower resistor that has been updated to a new design which is a single piece unit. If your truck has the two piece resistor, both pieces must be removed before replacing with the new single piece resistor.
The following picture is of an original two piece blower resistor that has been updated to a new design which is a single piece unit. If your truck has the two piece resistor, both pieces must be removed before replacing with the new single piece resistor.
If you have any questions related to this post please email me at
info@the-electric-connection.com I just finished a video on this as well. Please click here to view.
75 comments:
Thank you, Thank you, Thank you!
Your instructions and photos probably saved me 3 to 4 hours in replacing the resistor and harness in my vehicle. Keep up the good work.
Outstanding post. This is a real time saver. The part from Electric connection was easy to use in the repair and even the very in experienced person could perform this task. Also great customer service for follow up questions. Thank you very much.
Thank You!! This post saved me alot of time. Using the great instructions here I fixed the problem easily. Thanks again
I just paid over $170 for the resistor and harness at the local Chevrolet dealership, feeling this was a bit much and armed with the part numbers, I found the Electric Connection!! I will be returning these parts to the dealership Monday and ordering from you, thanks a ton. Now if I can just figure out what to do with that extra $100........
I agree with everyone here..this has been a very useful site for a mediocre weekend mechanic like myself. Unfortunately, I have not resolved my problem. I have a 97 Chevy Silverado Z71. Blower was working on high only, but this morning I turned off my truck and the blower kept blowing. I came home and replaced the blower speed control switch, the relay switch down by the blower, and the resistor (not a job for someone with fat hands). I inspected the resistor and relay switch wiring harnesses and saw no scorched or damaged wires or marks on the harnesses. After all was replaced, still no blowing. Relay harness is 5 prong, with red wire being hot and purple wire going straight to blower. Resister harness is 4 prong. I tested all wires on resister harness and had no power to any of the wires. Checked all fuses in the cab on fuse panel and under hood, nothing blown. Could there be an inline fuse between the relay and resister harnesses? Does power for the resister come from one of the wires coming from relay harness? I hot wired the blower straight from the red hot wire of relay harness directly to the metal prong on the outside of the blower, and blower worked. Purple wire from relay harness goes straight to blower, so I used a jump wire from the red hot lead on the relay terminal over to the purple lead on the relay terminal and blower worked again, but when I plugged in the relay switch, no blowing. Could control panel in dash be defective and not allowing any power to get to the relay switch via the blower speed control switch? Blower also does not blow as hard as it should? Any help would be greatly appreciated....it's getting hot in West Texas!!
Hi Mike C,
You either have a blown fuse or a poor connection at the blower speed switch. It is very common for the terminals on the brown and orange wires to be heat damaged and so loose that they do not make contact with the switch terminals. In the future please contact me at the
info@the-electric-connection.com address.
Thanks, Sparky
Another problem. My 99 Suburban blower works in all postions very well and MOST of the time on high ok. The red wire for the blower is a DIRECT feed and gives the blower full 12v. When the blower speed is on anything but high, power goes thru the resistor module. Occasionally, we have to slap the wire harness down underneath the dash on passenger side to get it to turn on in high mode. I then felt the connector that connects the two red wire ends and it was hot as fire. also, the red wire was hot about six inches or so on either side of the black connector. Does this mean my connector is bad?
Yes,if you can unplug it you will see burn damage. To have a lasting repair you must replace the resistor and harness connector at the same time. Replacing one without the other will lead to a very quick failure. To order parts be sure to go to www.The-Electric-Connection.com
We have similar problems with the 03 trailblazer. I bought a new resistor and harness. The old harness has three wires and the new one has seven wires. How do I make this work?
You don't. If you have a three wire connector you have auto a/c controls and you are dealing with a blower control module and not a resistor.
Thanks Sparky- you helped me find the problem. I'll be ordering the part from you as soon as I finish writing this.
My 2004 Silverado with 114,00 miles started giving a blower problem last year. I still had setting #4, but no 1,2 3 or 5. Since it still had #4, I contined to drive it. Yesterday, #4 went out. A quick search on the internet and I found your site. Thanks.
In my case, I looked at the resistor connector and the resistor itself. On the resistor itself- prongs for wires A and B were fine. Wire "C" was slightly darkened. "D" prong was fine. "E" prong was melted and rusted. "F" prong was rusty. And "G" prong? Well G did not exist any longer. There was nothing but molten plastic in the area that used to be "G".
I'll be getting the one-piece resistor, and the harness plug. I don't know who the electrical engineer at GM was who said this was an adequate design. I may end up beefing up the wires myself for good measure.
Thanks again.
Jim
Sparky, Awesome information. My brother-in-law, who is Mr Goodwrench, and a top notch mechanic (mostly Buick), didn't tip me off to this. He had been 100% on his helpful info to date. I had already bought a blower motor from the scrap yard on his recommendation. "E" & "G" were melted beyond recognition, and the clip was melted to the resistor, with some collateral damage to a couple other wires. I am going to order the parts from you right now. Thanks for the helpful information. You saved me a bunch of time and screwing around!
I had the a similar problem with my 2004 Chevy Silverado, but only found that the circuit board on the original resistor had burnt and I lost speeds 1,2 and 3. However what I found trying was a replacement. I got one from my local parts store and when they asked me if it was 2 or 4 hole I told them 2 since that's all that was on the actual resistor. What I didn't realize was that I had to have the 4 hole because the 2 does not line up with the mounting holes due to the cover of the original being where the two screws mount the resistor to the heater assembly and the cover does not fit over the new one. The 4 hole is $20-$30 more than the 2 hole, but it worked. Thank you for your help, it was an easy fix, you saved me another headache and a bunch of money! I have already referred others to your site.
Sparky, HELP!
2005 Silverado
Started having problems with the AC working intermitantly. Would smell strong electrical. Then it stopped working on the highest setting (5) all together, but worked in every other position. Just replaced the resistor and pigtail and it works great on every setting other than high (5). Is it possible I have damage at the switch? When I replaced the parts, the black was where the 'heat' was, melted the connector and wiring pretty good.
Thanks!
Replace the blown 40 amp BLWR fuse in the underhood fuse box and all will be well.
I cut the bad connector wires all at once and blew the 40 amp fuse under the hood. Disconnect the battery before starting this repair and save yourself time and money.
Mine is an 05 with the digital hvac and my resistor only has 3 wires on the connector. Do you know why?
Your truck has auto a/c controls and uses a solid state blower speed controller. Please look at the posts that I did on 09/29/09 and 05/23/09 in the archives. There are links within the posts to purchase the speed controllers if you would like to.
Sparky,
I believe that my 2004 Silverado has the blower control module. It has five wires and what appears to be a "heat sink" on the top side where it fits into the case. The blower was running one morning when I went to get in the vehicle, I pulled the fuse for the blower motor and it stopped. Do you know which part I need. Your pst referenced the links in posts from 9/9/09 and 5/23/09 but I couldn't locate teh links? please help.
Hi Chip,
From your description your truck has auto controls and you should read the info at this post.
http://www.sparkys-answers.com/2009/09/2004-chevrolet-silverado-blower-will.html.
For ordering your part please either follow the links within the post or go to this link address.
http://store.the-electric-connection.com/Product547
sparky,
the a/c would run on settings 1-4 and not on 5. I replaced the blower motor resistor and wiring harness at the same time and it ran for about 5 mins and stopped. The blower now doesnt turn on at all. I have looked at all the fuses and none are blown. Any suggestions?
thank you
Jason
Hi Jason,
We have been seeing quite a few of these aftermarket/import resistors failing. More than likely you will find a lack of ground at the blower motor, even though terminal"E" black wire is good. I would strongly recommend going back to your parts store and see if they will upgrade you to the Delco parts. If not ask for a refund and oder them from
www.the-electric-connection.com
In the meantime put your old resistor back to work so that you will have speeds 1-4.
Sparky,
Happy with the help that Sparky gave you? Click on the following link to Thank Sparky!!
http://store.the-electric-connection.com/Category106
Hi Jason,
Glad I could help. In the future though, if you have other vehicles or have friends and family with GM trucks or SUVs, please consider The Electric Connection.
www.the-electric-connection.com supplies the most current design AC Delco resistors at lower cost than local parts stores and as you know from first hand experience, technical assistance through this site.
I have a Chevy with blower problems. I replaced the resistor after loosing #1, then #2, then#3 about 6 weeks ago. Everything was fine for the 6 weeks, then while on Hi, (#5) it quit again. I replaced it again and 4 days later it smoked it again. The 7 wire plug and terminals look fine, but I'm thinking of replacing it anyway. My question is - Would you know the OHM reading across the blower motor terminals? If that's low then I'll be drawing too many amps which could be causing the problem. The blower works fine on all speeds, it just keeps popping the resistor.
Thanks
A lot of people are having the same problem. If you check the resistor assembly there will be an open circuit from the black wire at the blower motor connector to terminal"E" on the resistor. This is caused by an aftermarket design flaw. You may order a quality AC Delco resistor from www.the-electric-connection.com or insist on a Delco upgrade from your current supplier.
Sparky,
Happy with the help that Sparky gave you? Click on the following link to Thank Sparky!!
http://store.the-electric-connection.com/Category106
Okay this infor is all fine and somewhat helpful. What about same issues for a Chevy Tahoe 2005. connector has been replaced the blower works fine, yet now it won't shut off with engine off.
Sparky, blower fuse was blown. Replaced the fuse and high setting now works! However, I wonder what would be popping the fuse in the first place. What advice do you have?
Hi Ethan,
One of two things usually cause the fuse to blow. Number one, as in your case the red battery terminal lead will melt and wind up causing and internal short within the original resistor. Second, some of us, myself included will get a little carried away when cutting the wires and splicing in a new connector, that we will short the red wire to the black wire and blow the fuse. Best to disconnect the battery or at least pull the BLWR fuse in the underhood fuse box before working on it.
Hi,
I have a 2005 Chevy Tahoe, fan won't shut off with the engine off. Blower works good on all speeds tried it on a different vehicle. Connector was replaced but the problem is it won't shut off with the engine off.
I will need to know if your Tahoe has auto or manual controls?
I have an 05 2500HD duramax. Blower just quit all at once at all setting and I smelt something buring. Resister and harness were burnt. Replaced them both and it worked fine for a week. Now today driving and it happened again. Blower does not work at any setting and I could smell burning again. Is it the motor or just bad resistor/harness again?
Where did you get your parts from? There is a big problem with the asian import units. A good resistor will either come in a Delco box or there will at least be a country of origin stamped on the green portion of the resistor. All of the Delco units have "Made In Slovenia" stamped on them currently.
I got the parts from Napa. I am not sure what the brand was.
You will need to go back through the voltage and ground tests outlined in the repair post above. If lower speed voltages are missing and you smelled a burning smell, I would suggest looking at the blower switch and harness connector. If all tests are okay, then your resistor has failed and I would recommend buying a genuine Delco part from
www.the-electric-connection.com
I have a 2004 2500HD Duramaz and the blower runs with the key off. I have automatic controls. The fan works at all speeds it just won't stop.
Steve
I did a post about that repair on 9/29/09 for a 2004 Silverado. There are links within the post for more testing information and where to buy the parts from. The following is the actual post address. It will not be active within the comments but you can copy it and paste it into the address bar at the top of your browser.
http://www.sparkys-answers.com/2008/07/2005-chevrolet-silverado-blower-inop.html
Sparky,
Your blog might have covered this already but I am new to the site and am very impressed. I have a 2003 Trailblazer and recently replaced the battery. Now my middle vents do not blow air regardless of the A/C settings (on or off,cold, colder, ..., fan speed 1-5). Air will blow through the side defrost vents and back vents....I have been told by the dealer and other certified GM repair shops that it could be the acuator, the "computer" , etc but until they hook-up they cannot be for sure.
This happens very often and yes I have covered it at the following post address. You will need to copy and paste the address since I cannot install a link within the comment area of this site.
http://www.sparkys-answers.com/2009/05/2003-gmc-envoy-no-ac-vent-control-b0263.html
SPARKY IM HAVE THE SAME PROBLEM EVERYBODY ELSE IS HAVING 2005 CHEVY TRUCK , I HAVE REPLACED THE RESISTOR AND PLUG NOW IT WORKS ON 5 BUT NOT 1-4, RAN A TEST THROUGH THE PLUG COMING FROM THE SWITCH AND IM GETN ALL THE SPEEDS 1-5, PLUG IT UP IM ONLY GETN 5 AT THE PLUG GOING TO THE BLOWER. IF I PULL THE PLUGG HALFWAY OUT IM GETN 3-4 , SCRATCH N MY HEAD HERE IN SUFFOLK
You will need to do your voltage tests again but this time do it with all of the connectors fully installed. You will need to backprobe the terminals from the rear of the seven wire connector. Also go back over the wiring order and make sure it is correct according to speed selected and letter designation. Let me know what you find.
I thought I had the same problem. I replaced the motor resistor and none of my speeds came back. The leads all looked good and none were melted. Yesterday when I went to select a fan speed, the dial was frozen. I turned it with a little force and got it to move. The fan would work on speeds 1-3, next it would blow the high speed no matter what number it was on and wouldn't turn off at all, except when the truck was off. Now, none of the speeds work. Could it be the motor or is there is switch in the dash that needs to be changed?
You will most likely have a failed blower switch with a damaged harness connector at the blower switch. Go back to the resistor and disconnect the 7 wire harness connector. Turn the ignition on and check the voltages according to the test chart in the post, as you cycle the blower switch through each speed. If the voltage signals are not correct, you will need to remove the a/c control head and do a visual inspection.
Hello Sparky,
I've got an 04 GMC sierra. The ac works on all settings except sometimes on the drivers side the cold ac turns hot. AND when the ac is running i get a really annoying sqeaking sound that comes from the lower passenger compartment. I disconnected the resistor to see of anything was bad and the small 2-connection pigtail is melted at the purple end of the connection. the 7 pin connector looks perfectly fine. Thanks for any help.
You have several different problems. You likely have a faulty driver's blend door actuator causing your temperature control problem on the driver's side. Your squeaking noise and burnt connector are due to a faulty blower motor. The connector will also have to be replaced. The connector is part of the blower resistor assembly. The resistors have been updated and require replacing the seven wire harness connector as part of the upgrade. I am enclosing link addresses that will have to be copied and pasted into your address bar as this system does not currently allow links within comments.
http://www.sparkys-answers.com/2009/09/2004-chevrolet-tahoe-blows-hot-air.html
http://store.the-electric-connection.com/Product563
http://store.the-electric-connection.com/Product575
http://store.the-electric-connection.com/Product497
Awesome blog, let me share my experience. My fan had stopped working on 1, 2 over a year ago, but I still had 3, 4 and 5. Last week the fan stopped completely, I pulled the resistor... half of the green circuit board was gone. It looked like someone took a scroll saw and cut it in half. I found the missing piece against the cabin filter. The harness looked great, so replaced the resistor, but still no fan. I followed Sparky's instructions, checked all the wire connections with a meter and the harness was good, right up to the blower.... I pulled the blower, cut the old harness from the blower to the resistor and bared the end of those wires and connected them to my battery and was able to get the blower running (I say was able since the fan was harder to turn when I removed it, didn't spin easily) I've now ordered a blower as well along with a set of cabin filters. The filters in my truck were filthy and no doubt contributed to the failure of the resistor and fan.
thanks to sparky and electronic connection this job was very easy to do just want to thank both of them took me about an hour of my time and there parts and saved me a ton of money thanks again
Dead on! Solved my problem and saved me much needed time and money. A million thanks. Baton Rouge, La
cooling on all 5 speeds are fine up to about 45-50 minutes and then can't feel anything out of vents, but still can her the blower at all speeds.. could it be a bad blower?
My first thoughts would be a faulty mode actuator that is shifting the airflow to the defrost and or floor positions, or a frozen evaporator core. From a faulty clutch cycling switch.
Great. exactly what I was looking for. Wish there where more sites like your
Thank you. This made the repair so easy
I have a 06 Chevrolet Trailblazer. From reading the post it sounds like I need to replace the resistor. Could this also be the reason why the last two times I had repairs made to the vehicle (the ony common factor was that the battery was disconnected both times) that you can hear the ac blowing but nothing comes out of the vents. It will blow out on defrost but not on any of the vents.
Yes it is. the mode actuator was worn and during the recalibration procedure, initiated by the battery disconnect, it over traveled and is now stuck. Please read the article relating to this problem under the category "B0263".
Why are you splicing wires during your resistor pack change out? If the wires are not burned the resistance should be the same. Is there a problem with the OEM design that causes the stock blower resistor to fail? Seems to me the resistor pack should not fail.
I ask because I had a failure on my '04 Suburban blower and pulled the pack. Everything was dry as a bone, but the resistor pack was blown apart in two places. Funny thing to happen after 100K miles. Anyway, a check of the wires revealed nothing. No hint of burned wires.
What am I missing?
The original circuit board type resistors had a high failure rate.GM updated the resistor to the current heavier design. This created a new problem in that the wires were not heavy enough to handle the load and became the new weak point. It is strongly recommended that the harness be updated to the heavier design when the resistor is changed. Regardless of how "good" it looks. Preventative maintenance.
I have a 2005 Chevy Silverado, and lost speed 5 ~6 months ago. I lost speed 4 today for an hour or two, and then it worked again. I went to my local chevy dealer on the way home from work, and he told me about the resistor problem. He also told me to check the wiring harness to see if it was burnt. There was one burnt terminal. Just to make sure he was right, I replaced the resistor and cleaned the burnt terminal and turned things on to see if it would work before I spent the money on a new harness. Speed 5 didn't work. I took the new resistor out, and reinstalled the old one so I can use the A/C until I can get to the part store to buy a new harness. After I plugged the old one back in, all of the speeds worked (even speed 5). Any idea why it suddenly started working?
Do I really need a new resistor, or do I just need a new harness?
Thanks,
David
You need both. The harness is damaged and it will transfer the damage to the new resistor.
hello sparky my name is ryan from wv i left work turned on heater and it worked on low but the fan wouldnt turn up when i tried to so i cut vehicle off and turned back on and it worked on high but wouldnt turn down so i then cut vehicle off again and the heater kept running. i have pulled fuses and tried reseting it but it still works like it stated whatever speed its on when vehicle is turned off in is what speed it stays on. could u please tell me what might be wrong and where to begin adn what parts im looking at. thanks my vehicle is a 2007 chevy trailblazer with dual controls and either auto or manual heat controls.
I would suspect a faulty blower speed controller. have you done any testing or inspection?
Sparky,
I just had the dealer replace the resister and fix the harness on my 2004 Sierra. They fixed the harness and replaced the resistor for free because of a recall. The issue I have now is that the blower does not kick in higher on speeds 4 and 5 when the ac is turned on like it did before the fix. It seems as though the speeds are all higher now but with out the change for ac or recirculate. I have the duel climate control, not digital. Is this normal ? of course the dealer says it is.
No, it is not normal. There should be a distinct difference in the blower output at every speed. What do you mean by no change with a/c or recirculate?
There is not a "recall" on the resistors and harnesses. There is a "campaign" for some full sized trucks and suv's. A recall would be mandatory and a campaign is voluntary at the manufacturer's discretion.
Also if you have it done, you stand the chance of something going wrong that will ultimately cost you some money. Just like you are experiencing now.
Actually they extended the warranty on that particular problem, if the blower was to become inoperable on any or all speeds they would cover it under warranty up to 150000 miles. There IS a distinct difference in speeds at all 5 settings BUT before the "fix" I guess you could say there were two more speeds when the ac or recirculate was on. When set to 4 or 5 I got MAX ac which I don't get now but all the different speeds seem to be a lot higher then before I hope this is clearer, Thanks
With the blower on high, switch between max and normal a/c or push the recirculation button on and off. Allow 30 to 60 seconds for the recirculation door to fully move. You should, as you stated, be able to hear an audible change in the sound of the blower. If not the recirculation actuator is stuck. Probably happened when the battery was disconnected to work on the blower issue. I do not recommend disconnecting the battery to change the resistor harness. Instead, remove the 40 amp blower fuse in the underhood fuse box. Also make sure the ignition is off.
Sparky, thanks for all your help but I now have a different problem in my 06 Silverado 2500HD. My blower is acting very strange. After troubleshooting for hours I have firgured out what is kind of going on. Let me explain.. When I first turn key to RUN blower turns on, but when I start the engine the blower completely shuts off. Here's where it get's weird. When I shut engine off and turn key back to RUN the blower does not turn on.. So after a lot of frustration I figured out that if I wait 3-4 seconds before turning key to run the Blower will work. So in order for me to use the Blower while I am driving I have to turn key to RUN and then turn the Key towrads START just enough to kill the power to Control Unit but not start the engine. I have to hold it in this position for the same 3-4 seconds before starting engine for the blower to work. I am going crazy trying to figure this out. Have you ever seen or heard of this before? I have replaced the Blower Speed Control Mudule and I have swapped out the actual main control unit in the dash. Please help me. Thanks, Nick
Since you stated that you replaced the blower speed control unit, I am assuming that you have auto a/c controls and you installed part number 15-81728. If so the blower motor will need to be replaced. I have included a link address to another post that will shed some light on the subject. Copy and paste.
http://www.sparkys-answers.com/2011/07/2003-gmc-yukon-bower-erratic-not.html
I have a 2001 GMC that was only working on 4 and 5. I replaced the resistor and changed the hvac fuse that is under the hood. I checked the resistor harness and all the connections look fine, no burnt look, etc.. Now I am only getting my blower to work on high. I checked the voltage on the harness and all are getting 12 volts on their settings. Any Suggestions??
I am working on an 03 chevy 2500, single cab, base model truck. Someone bypassed the resister and wired a jumper wire from the blower to a toggle switch.Only the a/c would work and only one speed on the blower. I removed the jumper wire and replaced the resister. Nothing on any speed. I checked the wires going to the harness and the red wire is hot. The rest are dead on any speed. I checked the fuses inside the cab and all are good. I then checked the brown wire going into the control panel and it is dead. I wired a jumper wire from the fuse box to the harness going into the control panel and got all speeds but 5, and no heater or defroster. Before I learned about the bad resister I replaced the control panel. Both the control panel and the resister were replaced with ac delco parts. Any idea what may be the problem?
Thanks
Randy
I have to assume that you connected a new fused wire to the brown wire terminal at the blower switch. There are other smaller brown wires that go to some of the other connectors. You will need to look at a wiring diagram to see how many are involved to see if you want to do the same bypass. I have been told by others that the wires can be damaged somewhere around the instrument cluster area. No personal experience with that though.
Hi 2001 GMC,
Assuming that your test of the lower speed circuits was accurate, the new resistor is faulty. The 7 wire connector will need to be checked with it disconnected and the key on. Most of the time a simple test light or voltmeter test will suffice but in unusual cases there will need to be a load applied to each individual circuit while testing. Ie a headlight bulb with one lead connected to chassis ground.
I am having similar problems as this thread. I have an 06 Trailblazer where the blower either works or doesn't. Sometimes with it getting stuck on with the key off. When it is on I don't have control over the speeds, sometimes just a trickle and other times on high. It is an automatic unit with dual control. Also have noticed a voltage drop when idling. The battery and alternator have been changed recently. Any help would be greatly appreciated thanks.
The Trailblazer and Envoy use the same auto a/c, blower speed controller so the following information should tell you what you need to know. As far as the voltage drop at idle, it is relatively normal but if it seems excessive and the battery has been disconnected in the recent past, the throttle plate may ned to be cleaned.
http://www.sparkys-answers.com/2009/09/2004-chevrolet-silverado-blower-will.html
Thanks so much for your post. I am a mother of three who is not afraid to at least try to fix something. This post and many others on your website saved me a bunch of money I am sure. I accessed the vent parts by taking off the black cover under the passenger dashboard. I first inspected the blower resistor wires. The wires looked good and were not burnt. When I unhooked them, the connectors looked fine too and then I looked at the blower resistor and the green computer chip was obviously fried. I ordered the part through your link and it came in 2 days. I popped in the wires and was good to go. The repair took me all of 10 minutes once I found all of the tools I needed and I had no clue what I was doing. Thanks so much for the information in your post. I am so glad I did this repair myself!
Thank you so much for the information. You have save this single dad a lot of money.
I had pretty much the same issues on my 2003 Trailblazer (with Auto), Blower running with key off. Replaced the resistor with harness(Echlin). Now I have have to pull the fuse while the truck is running to get the blower working. Otherwise everything works fine while the trucks running. Kinda like a computer reboot?
Your blower motor will need to be replaced. Please read the information at the following post address. You will need to copy and paste it. Pay particular attention to the end of the article in red font.
http://www.sparkys-answers.com/2011/07/2003-gmc-yukon-bower-erratic-not.html
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