EduBarbosa

Hey guys,

I'm new here! Wanted to find help regarding a problem that is happening in my old Audi A4 B5 8D0 1995:

When I press the AC button, it won't stay ON. My mechanic says that it's not ON even if we let the button pressed. I thought it was the AC module, so I ordered one used one.. it did not solved the problem. Re-ordered another, the same.

Can you guys help me identify the problem?


Thanks in advance,
Eduardo

Cybersombosis

Have you tested the pressure in the system? It won’t allow the compressor to engage unless there is enough pressure in the system and enough refrigerant. The pressure switch is what triggers the compressor clutch to engage, allowing refrigerant to circulate. You can get a home kit and try a can of refrigerant and see if that helps. The kit will come with a pressure gauge and you can check if it is in the blue zone. It’s most likely not and too low.

EduBarbosa

Hey, my mechanic already checked the pressure system, eveything was working fine in there!

desertsage

Your '95 A4 probably has high and low AC pressure switches. A scan can tell you if one or both of those is inoperable and not letting the compressor engage, like Cybersombosis said. Your compressor is OK? Maybe your mechanic has already confirmed that the switches are working.