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A/C Blower Won't Turn Off??

41K views 8 replies 8 participants last post by  eashbaugh 
#1 ·
When I turn off my car, the a/c blower keeps blowing at med-hi. I have the dual automatic a/c system. When the cars on, and you turn on the system, everything works but you can't control the speed of the blower. When you turn the system off or turn off the car, the blower stays on. Anyone ever have an issue like this? And can anyone help me?:confused:
 
#2 ·
When I turn off my car, the a/c blower keeps blowing at med-hi. I have the dual automatic a/c system. When the cars on, and you turn on the system, everything works but you can't control the speed of the blower. When you turn the system off or turn off the car, the blower stays on. Anyone ever have an issue like this? And can anyone help me?:confused:
yes I believe it is the blower resistor... try tapping it ... you will have to disconnect your battery if it doesn't shut off otherwise it will drain your battery... there was a user a few days ago that posted this same problem...
 
#3 ·
The auto AC system doesn't have the resistor ass'y; it has a PWM motor driver module instead. Don't recall any of those being a problem though. Maybe a search would come up with something. Probably either that module or the controller that drives it. How do you get it to turn off now?
 
#4 · (Edited)
My wifes car is experiencing this problem as well. We first noticed a problem with the blower not even coming on, but with the vehicle in motion some cold air blew from the vents. Now the blower works somewhat but wont shut off when key in the off position. Removed the HVACB fuse from the backseat fuse block.

Thanks in advance
Rick
 
#5 ·
A few things to consider from service information:

When the vehicle is moving, air flowing over the vehicle increases the air pressure just ahead of the windshield. This forces air into the outside air inlet, into the HVAC module and out through the floor and windshield outlets. Since the A/C compressor is not running, the incoming air may be warmed but not cooled.
This applies to vehicles built after February 5, 2006 and/or earlier vehicles that have had the HVAC control module updated (automatic air only):

The blower motor will turn on approximately 10 minutes after the vehicle is shut off. The blower motor will run continuously for 10 minutes at a 30% duty cycle. The afterblow function will only activate if the air conditioning compressor was engaged during conditions of high ambient temperature. If the vehicle is started within 10 minutes of the last key off, the afterblow function from the previous key cycle will be cancelled.
Hopefully this clears up some concerns; but Trailblazer210 may need the controller updated if unable to control the fan speed manually during operation
 
#7 ·
Same issue with Blower speed

Replaced blower motor resistor and boom..... Works like new.... Holding my breath for a few days that it keeps working fine.... I read somewhere else that when someone replaced theirs it worked for a bit but malfunctioned again.... Pretty easy fix if you can contort your arms up underneath the glove box.... Great videos on youtube will help with DIY repairs...

thanks all!
 
#8 ·
Blower won't turn off

I have an '08 with the twin auto climate control system and mine started doing the same thing this morning.... the blower continues to run after the ignition is turned off. Also, in manual, I cannot vary the fan speed. Is my problem also the blower resistor? I also read above that the climate control systems do not have this resistor? Who has the correct story?? :crazy:

Thanks in advance!! :thx:thx
 
#9 ·
Not the resistor

I had the same problem with my 05 Trailblazer. I replaced the resistor pack and thought it had fixed the problem, but the OSA temp was cooler and the problem didn't exist, as soon as it went above 75 deg or so outside it started again. I think it has something to do with the OSA but can't find a good wiring schematic to really troubleshoot with.
 
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