1996 850 a/c electrical problem

Peter Turner · Post by **Peter Turner** » 06 Jan 2008, 04:49

Hi,
I have a 1996 850 with manual a/c. It has an intermitant a/c problem and I suspect the a/c relay may be faulty but I don't know where it is. I removed the glove box and there are two small green relays there. Is it one of these please?
Thanks. Peter

Post by **Ozark Lee** » 06 Jan 2008, 08:22

I removed the glove box and there are two small green relays there. Is it one of these

Yes,

One is the max fan relay (Speed postion 4) and the other is the A/C relay.

If the relay doesn't kick in when you turn on the A/C check the A/C - REC switch itself. They are prone to failure.

...Lee

Peter Turner · Post by **Peter Turner** » 06 Jan 2008, 15:37

Hi Lee,
Thanks for the reply. May I ask one more thing please? When the a/c switch is turned on, most times the blue light doesn't come on, if it does come on, it goes out after a few seconds of the engine running and leaves me with no power to either side of the pressure switches. How is this a/c switch fed? On the drawing it appears to have the same feed as the recirc switch which always seems to have power. One more thing, if I apply 12v to the grey (outgoing) side of the low pressure switch the comp runs ok but neither of the switches has power coming in. (both are closed) does this sound like the a/c switch? Oh yes I removed both relays and applied 12v and they both close ok.
Thanks for the help
Peter

Post by **Ozark Lee** » 06 Jan 2008, 19:54

Peter,

Your symptoms are the classic problems for a bad AC/REC switch. Mine behaved exactly as you described when it failed.

You can often verify that the switch is the culprit by removing the radio - you do have your code don't you? - and simply squeezing the AC/REC switch.

If you are fearless, clever, and have a spare US $125.00 in your wallet to buy a new switch if you fail - you might be able to fix the switch. Here is link that will help

https://www.matthewsvolvosite.com/chat/p ... c&start=50

...Lee

Peter Turner · Post by **Peter Turner** » 06 Jan 2008, 20:08

Hi Lee,
Many thanks for all your help. You were 100% right! Although the switch showed closed on my multimeter, no voltage was going through. I proved it by bridging out the switch. Unfortunatly in my efforts I dismantled the switch module which sprang apart. A new one has been ordered and is on its way. Again, thank you for taking the time to help, it has solved a problem which has been driving me crazy for a long time.
Regards
Peter