TROUBLESHOOTING: Interior climate control fan and A/C at idle

[TheFugitive]

I tried searching before I posted, but I could have missed something. Forgive my ignorance.

My fan for the CC system works most of the time. However sometimes upon startup the fan/blower will not work at all. I'll check and the setting is on full blast, but no air coming through the vents. After about 10-15 min of this, it'll kick back in.
Since the blower motor does work the majority of the time, my suspicions point at the resistor/controller (part #8K0820521). Any thoughts?

The second issue is that at a stop the A/C blows less cold than when i'm running, when I get back on the throttle it will return to the cold output.

[van462]

If you have a meter its not hard to check. The glove box is held in with 10-8mm screws. With it out of the way you have clear access to the motor and controller. 2 wires leave the controller for the motor, you can slide meter leads into the back of the plug with it still connected. It will read from around 7 volts at the lower fan setting to 12+ volts at the highest settings. If you are getting voltage at this plug the fan commutator/brushes are likely getting dirty/worn. I ulled mine apart and gave it an alcohol bath and cleaned up the commutator the best I could with a pencil eraser. It has worked pretty good and gotten another year of life out of it, but I suspect on the day I need defroster the most it will fail. If you pass the voltage check then a new blower motor is your best fix.

The second part is quite normal, the fans try and move enough air across the condenser while stopped but its not like the ram air effect of moving. The compressor is also running at half speed as well.

[TheFugitive]

Thank you for your reply! I will check that with a meter this weekend.

As far as the AC goes this does not happen on new cars, shouldn't that suggest something is going bad?

[TheFugitive]

Over a year later, realized I never posted the fix.

Although the blower resistor didn't seem like anything was wrong with it, Replacing it solved the issue.

Replaced part #8K0820521