replacing blower motor resistor on 04 envoy and need help

chaffin14

Original poster
Member
Aug 7, 2012
4
I am trying to replace the blower motor resistor on an 04 GMC envoy. I have got the replacement but the only issue is the connection. This resistor has a seven pronged connection and the one I'm taking out only has 3. I was told I needed a 7 wire pigtail but I'm not a wiring expert by far and was needing a little help getting this wired. Also wanted to make sure I was given the correct parts in the first place. Any help?
 

AtlWrk

Member
Dec 6, 2011
674
You were given the wrong part.

There are two different style HVAC systems: auto and manual. The 7 wire resistor pack is for the manual HVAC system. The auto HVAC (yours) uses a motor controller instead of a resistor pack. They look similar to eachother but are functionally different and have different connectors.

The resistor pack in the manual system tends to overheat its connector which warrants replacing the 7-wire pigtail you referred to but it has nothing to do with the auto HVAC system.

What led you to replacing it in the first place?
 

chaffin14

Original poster
Member
Aug 7, 2012
4
the blower would continue to blow even with the key out of the ignition. Also the front blowers weren't working. I had heard that you had to rewire because the 3 pronged connector wasn't made anymore and I saw him select the auto version in the computer but I wasn't sure. Do you have any idea of where to get the correct replacement part because the only 4 he had were with 7 and 5 pronges?
 

The_Roadie

Lifetime VIP Donor
Member
Nov 19, 2011
9,957
Portland, OR
The automatic unit is indeed supplied with a 5-pin connector now, but it should come with a replacement pigtail harness and instructions. The way the 5-pin works is that there are 3 wires coming in from the controller, and 2 wires go OUT to the blower motor.

The 7-pin resistor unit for the manual systems is totally different, and cannot in any way be made to work.

Go to this thread and check out my post #6
http://gmtnation.com/f23/04-envoy-blower-motor-blower-module-problems-277/
 

chaffin14

Original poster
Member
Aug 7, 2012
4
Thanks for the help guys. I'm glad I got on here and questioned before I stripped a bunch of wires when I had no possible chance of succeeding. I will be taking these parts back and trying to locate the correct ones.
 

Denali n DOO

Member
May 22, 2012
5,596
chaffin14 said:
Thanks for the help guys. I'm glad I got on here and questioned before I stripped a bunch of wires when I had no possible chance of succeeding. I will be taking these parts back and trying to locate the correct ones.

I changed mine a few weeks ago. My blower would run when the keys were removed too! This is the updated part I got to replace mine and it works fine now. Part # is on the box.
 

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The_Roadie

Lifetime VIP Donor
Member
Nov 19, 2011
9,957
Portland, OR
IIRC, we had somebody come here and describe his symptoms, and it turned out he WIRED the 5-pin harness into the 7-pin vehicle connector sort of at random, willy, nilly, and had a couple of left over wires and wanted to know what to do with them. Like the designers were goofy enough to leave a couple of functions not connected.

He's lucky he didn't have his blower speed control connected to his drive-by-wire accelerator pedal!
 

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