A/C clutch won't engage on 1994 940 wagon

bentrider · Post by **bentrider** » 15 Nov 2007, 03:33

The a/c quit working a few days ago and I noticed the clutch does not engage. I did not see a blown fuse. The fan does work. Anybody have any common things to look for when this happens?

Thanks,
Joe

Post by **billofdurham** » 15 Nov 2007, 11:46

After fuses the first thing to check is the refrigerant charge in the system. Is there enough in or is there a leak?

Bill.

bentrider · Post by **bentrider** » 15 Nov 2007, 14:12

Bill,
Whats the best way to test the refrigerant with the system not working?
Joe

Post by **billofdurham** » 15 Nov 2007, 15:35

Over here, where our 'nanny government' has banned the sale of refrigerants to individuals, we have to go to an authorised shop to have it checked.

In the US you can buy canisters of freon to top up your system. This would tell you if there was a leak.

Check out the Official AC thread in the Volvo Repair Database on this site. It is full of tips and advice.

Bill.

bentrider · Post by **bentrider** » 24 Nov 2007, 17:16

Bill,
After I posted on this earlier, the a/c started working again, then the car died due to a bad rpm sensor. Does the on board diagnostics also detect a/c problems?
Thanks,
Joe

Post by **billofdurham** » 25 Nov 2007, 11:33

The diagnostic unit in the engine bay only stores fuel and ignition faults.

On cars fitted with the Electronic Climate Control system fault codes can be read using the ECC unit but I believe that the '94 940 was fitted with a Manual Climate Control. I know that my 940 was. Therefore, it is not possible to read codes for the AC.

Bill.

bentrider · Post by **bentrider** » 25 Nov 2007, 15:51

Bill,
Thanks for the help. Now for some reason the clutch is cycleing every 5 to 10 seconds. I guess it is time to to add the 134a again. Could a faulty pressure switch cause this too? Thanks,
Joe

goldmember · Post by **goldmember** » 25 Nov 2007, 17:24

G'Day

I'd say the fault lies with not having enough pressure of gas. That is, you need to re-gas. This pressure is required for the A/C to engage. Otherwise the belt just turns the pulley, virtually, resistance free.

Correct me if I'm wrong, but the pressure switch is used to turn the A/C fan on. THe reason I suspect this is that a wrong pressure switch was installed in my 740 and the bleeding fan comes on all the time, regardless if I have the A/C on or not.

Apparently this is not an issue and to replace the switch means a re-gas, so I won't be doing that for a while.

I hope you have your problem sorted out.

Regards

George