Ac Problem

[Anaivi0713]

I replace the AC compressor, the expantion valve and the drier. After all the process of refrigerant etc. It worked for a few minutes then all the lines when from really cold to hot. What should I do?? What else can it be?

[June]

Check cooling fans/ clean condenser coils. Otherwise we need to know what the high and low refrigerant pressure is running to be more helpful. You did leave it at vacuum for five minutes at least once vacuum pump was off and closed to be sure no big leaks? June

[Anaivi0713]

Vacuum was done right. Coils are clean and fans are running...

[jimmy57]

The compressor is variable displacement. The evaporator in the case has a temp probe that reports air temp about 1 inch from evaporator. The climate control module gets this signal and then sends a signal to engine control module to request high, medium, or low compresor functioning. The engine control module pulses a solenoid inserted into side of compressor to control the compressor. The evaporator temp probe can cause poor cooling and if that is it the evaporator temp read out from the climate module will be wrong. On a 34C day before the car is run the climate control evap temp would be 34-38C. if it reports a much cooler temp like 13C then the compressor will not be commanded to higher output and it ill not cool well when everything else is working as it should. Another failure can be the solenoid inserted into compressor sticking. In that case the evaporator temp will be reported correctly and if you read a/c control signal from the ECM it wil be 75-90% but the low side and high pressure will be 95 and 115 respectively as the compressor will barely be moving refrigerant. VIDA or a scan tool that reads Volvo modules will have to be used.

[oragex]

Not necessarily related to the issue, but I found this interesting AC troubleshooting guide https://www.buyautoparts.com/howto/ac-p ... adings.htm