Justin Can

Hey

On my 2000 audi tt 1.8 FWD

the other day my ac stopped working while on the highway. was blowing cold and then suddenly stopped and was blowing warm air.

r-134a is fully charged.
Compressor is not engaging. hooked up a meter to the plug that connects to the compressor and am getting 12 volts.
Not sure why the compressor is not engaging?

Does anyone know if there are other sensors that would stop this?

Any insight would be helpful... not trying to bring it into the shop to have them tell me to replace everything

Lexx

replace the compressor. You can try and replace the pressure switch, but it is likely the compressor is bad.

been there. done that. got the tshirt

Mister Bally

If you have +12 volts with the load of the a/c clutch coil attached (disconnect first and verify the coil has resistance), you have a bad A/c clutch. Otherwise, use standard automotivetroubleshooting techniques to troubleshoot. There is an over pressure and under pressure switch for the refrigerant circuit, and a couple of sensors in the engine coolant lines. Also there is an ambient temperature sensor. Any one bad and the compressor clutch won't engage. Also, the $200.00 (for genuine) fan/clutch control module. Don't waste money on a Chinese knock-off. there are several horror stories on the net about them.

Peckols

Where is the port to add freon?? I can't find it haha

mobsTTa

before you go spending a ton of money
1st turn on ac, look at fans are they turning, if not replace 30 amp fuse on top of battery, the last one on the left as you face the rear of car.

worked for me

Mister Bally

Again, if you have solid 12 volts at the clutch power wires (not just a meter, also connect a brake light bulb or something along with a meter) The clutch is bad and needs to be replaced. Moving parts fail.

Josh Speer

This solved my problem thank you! The fuse box melted corroding the 30amp fuse.

vtraudt

I measure 4.5 Volt BETWEEN the 2 pins of the AC compressor connector (car side, pressure in system, AC on), and 12V to ground on one pin ,and somewhat less (like around 4 V?) to ground on the other pin.
Resistance over the compressor coil is 4.4 Ohm.
Cooling fans do NOT turn on.
I was able to 'click' the clutch (using a pigtail that fits on the compressor connector) with 12V.

Suggestions?