Ok I've searched all over this place and I haven't been able to find anyone with an issue like this. Turned the A/C on and the whole system went haywire. First off the electric fan kicks on and off constantly as soon as you turn the fan speed up on the climate control. Also the bars that show how high the fan is turned up on the climate control go up and down as the electric fan kicks on and off. It blows no air out of the vents. And no heat in the northwest sucks. I have replaced the climate control unit itself and the symptoms are the same. Where to look now? Is there any relays that could cause this? Location? Any help would be great.

 

blower motor? its in the cabin behind the glovebox

 

If its the blower motor, I may have one for you from a part out I hit up last year. I'll check for ya.

 

But would the blower motor frying cause the electric fan on the radiator to go on and off constantly? Other than the blower motor the only other things that control the fan would be any relays or the controller box by the intercooler?

 

you did not say electric fan in engine bay you said fan while refering to the hvac system thus leading to believe you meant the one that blows the air in your face. you did sate electric fan but both are electric. theres a relay panel diagram on the forums search for it, take out the hvac related ones. see if thta helps

 

If no air going through the vent, it would be the blower motor.

The electric fan in the engine bay is cycling, to what the hvac industry refers it to. Its probably going on and off because the blower motor isnt blowing out the cold air or no heat load. Hard to explain, but i got the idea in my head.

 

I have the same thing going on. Sometimes the A/C works and blows cold, but the interior fan blower cycles off for extended periods. It indicates that is shutting down on the control panel too. The bars drop off completely. It was doing the same thing to me in the winter and really sucked because its the defroster too. I gotta see out my windshield. I'm about to order a new blower unless anyone has a better idea.
I've got Vag codes "A/C pressure switch f129 open or short" and "Fresh air blower (V2) 17-10 control difference"
2000 audi a4 1.8tq atw

 

Ok I fixed mine. Looks like there is a resistor attached to the blower motor that was causing the fluctuations. I searched for a resistor and it was like a hundred bucks. Thankfully I eventually found a new blower and resistor combo ob ebay for forty bucks shipped. Brand new exact replacement, same part number 8D1 820 021. My car is a 2000 A4 1.8tq ATW. Popped this new one in and good to go. Oh the seller's ebay name is brementech, the listing is for "New Audi A4 S4 VW Passat Heater Fan Motor"

 

Thank you for the update

 

vgo, I love that pic of your car. It's beautiful, man.