Hi guys, this is on my '95 Volvo 850 GLT. I did some research and so far I still can't figure it out. Here are the details:

• Dash A/C light turns on
• A/C clutch doesn't engage when jumped.
• A/C clutch doesn't engage when freon is pumped in.
• I can force the clutch to turn with a bar.
• Freon is in system because I can press the needle and it will hiss.

I heard something about a A/C relay and a fan speed switch but am unsure where these are...

A/C did not work when I got the car due to leak. I replaced the suspect parts and vacuumed out system so it should be good to go...

Thanks!

 

Hi Annihilator,

I could be that there is not enough freon in the system even if you hear hissing sound. I believe there is a pressure detection swtich which disables the system if the freon level is low. This prevents the clutch from engaging and burning the compressor. I would bring it to a local garage who specialises in A/C systems and have them check for leaks and refill the system. It should be under a $100.

Good luck
T.

 

I know with other cars I dealt with, that even if the system is empty, I can still jump the clutch somehow. Maybe its not the case with volvo?

 

Man, most of these cars have a leak at the evaporator at this age. Take the car to a shop to have them let you know what's wrong. Unless you're going to pet gauges and service it up properly.

 

I have a set of gauges at my disposal but I am trying to figure out if its wiring, compressor, or something else that is bad.....

 

Is this the Manual HVAC or ECC?

In either case, you say the AC clutch won't engage when jumpered (12v to hot wire coming from clutch)? Then either the compressor has lost its ground connection or the clutch solenoid itself is fried. Ohm out the clutch solenoid; if it's open (infinite ohms) you need the clutch solenoid for sure.

 

Its a manual one. I tried jumping the low pressure switch I believe. When looking at the compressor, where do I jump it? I only see a 1-wire connector.

 

That's it; jumper 12V to that wire and see if the clutch "clicks" in... engine doesn't need to be running for this test.

If it does click, then clutch solenoid is OK. Now start the engine; turn on AC, and test for 12V on both sides of LPS (low pressure switch) while it's still connected; if good there, then do same for HPS (high pressure switch).

 

Ok, I will get back to you. Thanks

 

you can get it to move if you force it ? if its that hard your compressor is bad , did you take a voltage reading at the plug for the clutch to see if you have voltage ? if you do have voltage the clutch is burnt out . if you went with direct power from the battery and it still didn;t turn on bad clutch , mite of burnt out from bad compressor

 

Ok, clutch works when jumped... Now checking switches...

 

"Jumped" -- where?

The correct procedure is:

1- Start the car, turn the AC on at Max at Vent setting on the Dash Unit, open the doors.

2- Jump the 2 wires at the Low Pressure Switch (next to the Accumulator).

3- If the Compressor does not engage, unplug the connector at the Compressor and jump it from the battery. If it does not start again, your compressor is bad. If it does, you need to troubleshoot wiring.

4- If however the Compressor engages along with the Electric fan (Step 2), check for Refrigerant charge with $ 15 Walmart rattle-can.

If Refrigerant charge is around 25-30 psi at Low-Side, then you have to do electrical troubleshooting the the Low Pressure Switch and/or Control Unit (in dash).