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Eric, Automotive Repair Shop Manager
Category: Pontiac
Satisfied Customers: 32075
Experience:  20+ yrs. experience as repair shop manager and technician.
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2005 Pontiac Aztek: my fan blower control..smoothly..stopped working

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Hi - I have a 2005 Pontiac Aztek. For years , my fan blower control knob only worked at settings 3 and 5. Actually , the knob never really sat smoothly in the other setting detents, not even in "off". Now, the fan stopped working at all settings. The day before it stopped working, the air flow was just trickling out. I changed both the blower motor and the blower motor resistor, but still no heat or air flow. What do you think the problem may be?

do you have a DVOM(digital volt ohm meter)?
Customer: replied 5 years ago.
Unfortunately, I do not. I should have also mentioned that I hve also pulled and re-seated fuse #25 (climate control blower motor) and #44 (BCM) from the interior fuse box, as well as #28 (BCM) from the underhood fuse block. Thanks.

The most likely failure is in the climate control assembly itself, but could possibly be a short in the wiring harness, which is why i was aking if you had a DVOM to test before replacing the climate control assembly or tear apart the dash to trace a short in the wiring harness.

Customer: replied 5 years ago.

If I can get my hands on a DVOM, what steps would I take with it depending upon the readings I get? How difficult would it be to replace the climate control assembly if you think this is the problem? Would hate to go to the expense of this unit if you think it might be something else.


Here's some additional info to help you with the diagnosis.

AC Delco A/C Control Unit


The climate control unit has 3 rotary knobs. Left is for fan speed, center for temp, and right for vent selection. Below the left fan speed knob are two buttons - one for exterior air circ and the other for interior air circ. The right vent selection knob apparently works fine because it automatically causes the air circ button lights to switch from one to the other depending upon the vent selected.


Below the right vent selection knob are also two buttons - one for a/c and the other for rear window defroster. The rear defroster button works fine because it lights up when I push it. The a/c button is not activating/lighting, but then again the fan is not running.


Hope this helps with more insight. Thanks.


Ok, below are directions to remove the control assembly.




Ok, once removed, you will check for power going out at the highlighted wires in wiring diagram below:


if no power going out, then replace the control assembly. if power going out, then check for power on those wires at the blower resistor. if no power, then the wiring harness has a short in it.
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