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 this link
http://store.the-electric-connection.com/Product497
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. If any of these signals are missing you will need to inspect the blower speed switch. 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
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
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29 comments:
Sparky, Great post and really good pics. Keep up the good work. We all appreciate it.
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.
I can't say THANKS enough. Your pictures and description saved me many hours of labor and identification of the parts I needed super easy. Many THANKS again.
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........
GREAT TIPS/PIC'S THANK YOU. NEXT HOW DO I CHANGE THE BLOWER FAN???
On most of the later model trucks there is a finger lock that need to be released and then the motor will twist like a light bulb and pull out. I will try to find some pictures soon and add them to the blog.
All I can say is "you are my new best friend" Saved me a $89.00/hr shop charge
Hot in FL and my blower stopped working it had been on high for about 5 minutes into the ride,I immediately turned around and came home took dash apart checked for loose connections and fuses everything was fine I looked up blower problems for 2005 Chevy Sparkys Answers popped up I am no sort of mechanic but with your photos and directions I was able to find that the black wire had melted to plug of resistor I scraped black plastic from metal strip or whatever and inserted an old part of a staple made sure nothing was touching pluged it back in and I had an AC again..! Thank you so much. I did notice that it had became real hot prior to using the paper clip though I guess a loose connection isnt good. Thanks Again
Makes for a good emergency repair but will not last long. You are correct that heat is the problem. Keep in mind that the black, ground wire is between two hot wires and as it heats again, as it will, you will have short that hopefully will only blow a fuse. To properly repair please replace the connector and resistor at the same time and ASAP. You can find the parts you need in our online store by clicking here.
thanks! i had the problem where my ac would work on high only and checked the harness and all looked good and i had voltage everywhere you said i would have voltage. so i change only the resistor out and it worked like a charm. so i'm here to just say thanks. this problem was on a 2007 classic chevy crew cab just thought i leave a comment to maybe help anybody that was in the same situation that i was in. i hope i don't need much help from this site in the future but if i do i know where i'm going to check first.
thanks again
Great info. Did gm never issue a recall on this for the fire hazard.
Thanks. This post is the best. It took very little time and was right on the money. I would not have had a clue as how to isolate the problem and then fix it. The notes and directions you had on checking the voltage on each pin was great and I was lucky enough to only have to replace the resistor. Boy was it fried. Again, thanks,thanks,thanks.
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
Sparky, Fan went out completely. Took resistor out and at the plug the black wire show evidence of overheating. Bought new resistor and plug installed them and still no fan. Pulled plug and I have power to all the wires while selecting positions 1-4 but nothing on the orange wire in position #5? Any advise???
Is your orange wire in position "F" of the seven wire connector? If so you have a switch or wiring problem. If it is in position "G" you have a blown fuse in the underhood fuse box.
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,
This is exactlly what happened and I was able to regain speed control to my blower. I have sent this along to a friend with the same problem... his is an'06 Silverado.
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.
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