Blower Motor 4th Speed no work

Royalwapiti

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Joined
Jul 16, 2012
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82
The 4th speed died on my HVAC fan, is this something that is common, I see threads about resistors and connectors. Is this something similar? Looking for a place to start.


2006 LS EXT 4.2L
 
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That's where I started cause it seemed the easiest to check first when I had a position go out on me. Started with 4/5 fail then the whole thing didn't work. Turned out to be a burnt resistor/melted connector. Took 5 minutes to check and 30 bucks on Amazon for a Dorman resistor and plug.
 
"I" found this to be much easier than expected. The pain (if there is one) is taking it apart to see if the connector is bad as well. Our connector was fine, so we just ordered the resistor pack.
 
Har. I have the digital control system, and my connector overheated and failed years ago, so I rebuilt it instead of buying a new one. But if the FET inside fails, I have a spare already because I have a few thousand suitable ones in my lab. The 5 speed manual system is boring.
 
This is just common in general. In the past year I replaced the blower resister on my daughter's '03 Grand Am and my dad's '98 Prism.
 
Is there a how -to on installing and reseting the blower resistor on a auto climate control model? As I recall there is a sequence the control module must run through after installing the blower resistor(the one with 6 blades and five leads) and the refit wiring harness. The resistor was upgraded by GM to the six blade type for auto air models. Any how to info would be great as the reset process for the control module to run through its recalibration sequence is important. It runs through a process where it changes the fan speeds, door actuator modes, etc. before it can be used with the engine running.
 
Installing the speed control module for the auto/digital system is physically the same as the manual system's resistor pack. Couple of bolts and it sticks its heat sink into the plenum airflow.

http://gmtnation.com/forums/topic/2961-how-to-replace-blower-motor-resistor-pack-and-connector-pigtail/

http://gmtnation.com/forums/topic/267-04-envoy-blower-motor-and-blower-module-problems/

The wiring is slightly different in the newest updated modules, but they come with diagrams when you buy it.

http://gmtnation.com/forums/topic/6062-updated-part-s-for-auto-blower-motor-speed-module/

Reset has been discussed in almost all the HVAC threads, but it's as simple as pulling the HVAC-B fuse for 20 seconds, putting it back in, turning the ignition on and NOT TOUCHING any controls for 90 seconds.
 
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Did you take pictures of the FET install? I would like to see it so when MINE fails.........
 
When you take the module apart, it's obvious. It's a TO-220 package style FET. I found pictures at trailvoy, but there are threads here with broken links still from the before the forum software update.
 
Thank You. I am afraid mine will fail soon. 231,000 and orignal fan. I am holding breath....................
 
This took about 15 minutes, awkward position climbing up under the passenger dash. 6mm nut driver for the resistor, 7mm for the two screws holding the cover on under the dash. Fortunately the connector wasn't melted. I did this vehicle and my son did the blower motor resistor for his Nissan at the same time. Funny how Dad (me) got to buy both resistors...
 

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