jnsluft

I have the digital climate control in my car. Suddenly while driving, the A/C, or so I thought, just stopped. Nothing but hot air. After digging around under the dash, I found the A/C servo. I can manually move it and get cold air to blow in the car.

I do have working A/C, defroster control, and the fan works at all speeds, I just no longer have temp control.

How can I determine if the servo is bad, or if the issue is in the control unit?

Thanks,
Shawn

Harowing

might try plugging a digital multimeter into the connection for the servo, from the control unit and setting it to 20volts dc(or 12 volts, if yours has the option for it, but 20 will do just fine) then watching what it does when you change the setting, it should read power if the control unit is working.

Harowing

oh also(ive never worked with the electronic control unit) if i had to guess there is probably 3 wires, only 1 of them will be ground...so that +1 of the others will cause power.. (if i had to guess it'll prolly be brown for the ground, seems like most/all of the grounds in my audi are brown)

jnsluft

Does anyone know which wires they would be? I have removed the panels under the dash and have unscrewed the control unit. The volt meter is ready. I just need to know where to look.

Thanks,
Shawn

Harowing

Well like I said I've never worked with the electric unit before, but I believe the temp control flap is on the top on the driver side of the heat/ac blow box, should be just to the right of your heater core( I'm assuming the servo or vac pump or whatever it uses will be on the top like the manual control setup) but I might be wrong, either way there should only be 3-4 different places with servos(I'd think anyways?) so if they can be unplugged ya could just disconnect 1 at a time figure out which it is and maybe label for future reference as ya go(maybe even put voltages on the tags so if somethin happens in future you know for certain what it's sposed to get[prolly 12v but ya never know])

jnsluft

OK, Here's where I'm at now. I disconnedted the battery, and took out the climate control unit. I then removed ducting behind the console. I then removed the temperature control servo. I disassembled it and cleaned the motor. After replacing the servo, there was still no movement while changing temperature. I checked the diagnostice codes and it showed 8.3, 8.5, and 8.7.

So now, do these codes need to be cleared before the servo will move, or do I need to replace the servo. And with installing a new servo, will the codes clear on their own.

Shawn