95 Volvo 850 T5R A/C compressor not working

Post by **phils94850** » 17 Jun 2014, 11:32

put some Freon in my car and it leaked out within a day. Long story short I figured out it was leaking from the Schrader valve where you fill the system, so I replaced and filled the system but now my A/C compressor wont come on like it did. I tried jumping at the high pressure switch and nothing, im not getting current at the switch. Im assuming without current to the switch no current will be going down to the compressor. I tried pushing in on the compressor clutch and nothing.

Does anyone know how the current should run to activate the A/C compressor after you turn it on all the way to the compressor itself so I can back track and figure why im not getting current. ? I checked all the fuses and they are good.

side note.. a buddy of mine that runs a indie Volvo shop here said that sometimes the computer will get a low pressure code and wont let the compressor come on and I have to have the codes cleared but im not getting a CEL or anything ??

Post by **Ozark Lee** » 17 Jun 2014, 18:32

The easiest way to track this down is to measure voltage at the low pressure "pressostat". With the A/C on (Light off) and Fan switched on you should have battery voltage on one or both wires at the pressostat. If voltage is present there then the problem lies at or downstream of the low pressure switch which could include the high pressure switch, the thermal fuse, or the clutch. If no voltage is present at the pressostat then the problem lies inside of the cabin with either the control head or the AC relay.

If you have good pressure on the system and the pressostat reads an open circuit then the sensor itself could be bad but that is rarely the case.

To your original question on how much current the compressor draws, I don't know exactly but if you have 12ish volts at the compressor it should engage.

...Lee

Post by **phils94850** » 17 Jun 2014, 19:13

Thank you Lee for all the info !! I decided to unhook the battery for awhile, hooked it back up and i pulled out my glove box and messed with the relay and it started working

. I also found I guess a loose connection at the wires in the picture below, I guess it goes to the thermal that's on top of the compressor ? Ive read it can be byspassed ? has anyone done this ? I can mess with the wire and the compressor will kick on and off. At the moment, everything is working

Heath720 · Post by **Heath720** » 17 Jun 2014, 20:52

I have same type of problem going on with mine... Yes you can cut and splice after the thermal.

Post by **phils94850** » 18 Jun 2014, 06:24

Did you bypass your thermal ?

Post by **abscate** » 18 Jun 2014, 06:44

Phil - are you ready to throw 1000 USD at this AC? If the Freon goes in 1 day, your system is essentially open to atmosphere and will have a lot of water and corrosion in it. Something to consider.

Post by **phils94850** » 18 Jun 2014, 14:31

It's working great for now.