a/c no go 98v70

nburlie · Post by **nburlie** » 24 Jul 2007, 20:46

My compressor won't come on,I've charged the freon and checked fuses.I managed to jumper the a/c relay under the hood and compressor comes on and system blows ice cold.I can't turn off the a/c when it's jumpered from inside car,any suggestions??

thanks nick

Post by **Ozark Lee** » 25 Jul 2007, 07:26

Do the A/C and REC lights come on when you turn the respective switches on?

...Lee

rb2 · Post by **rb2** » 25 Jul 2007, 08:00

When my '94 850 had the same problem, it turned out to be a bad pressostat.
Replaced it with one from my local Volvo salvage yard and it fixed it right up.
Good luck

nburlie · Post by **nburlie** » 26 Jul 2007, 06:34

Ozark Lee wrote:Do the A/C and REC lights come on when you turn the respective switches on?

...Lee

Yes they do and I 'm pretty sure I can hear the fans come on as well.

Post by **Ozark Lee** » 26 Jul 2007, 06:57

If the lights are coming on at the climate control head unit and the compressor does come on with the relay jumpered that pretty much narrows the problem down to either the wiring from the ECC to the relay or the relay itself.

...Lee

Klausc · Post by **Klausc** » 29 Jul 2007, 11:36

nburlie wrote:My compressor won't come on,I've charged the freon and checked fuses.I managed to jumper the a/c relay under the hood and compressor comes on and system blows ice cold.I can't turn off the a/c when it's jumpered from inside car,any suggestions??

thanks nick

Because the AC relay is behind the glovebox, which relay did you jump? The pressostat on the line that goes through the firewall? If so, replacing the presostat switch is easy to do, system maintains it's charge.
Klaus

nburlie · Post by **nburlie** » 03 Aug 2007, 13:32

Klausc wrote:
nburlie wrote:My compressor won't come on,I've charged the freon and checked fuses.I managed to jumper the a/c relay under the hood and compressor comes on and system blows ice cold.I can't turn off the a/c when it's jumpered from inside car,any suggestions??

thanks nick
Because the AC relay is behind the glovebox, which relay did you jump? The pressostat on the line that goes through the firewall? If so, replacing the presostat switch is easy to do, system maintains it's charge.
Klaus

thanks Klaus
,the relay i jumpered is in the "Main fusebox" nearest the airbox and is marked a/c compressor,I tried jumpering the pressostat in the line near the firewall to no avail.I haven't tried to replace the a/c relay due to cost{$50}and am hoping to find one from a wreckers to try.any other ideas?
thanks Nick[/quote]

dumfree · Post by **dumfree** » 04 Jun 2008, 22:29

I have almost the same problem. I checked fuses, AC relay, compressor clutch - all is OK. ACC control module sends "AC request" to the ECC module, but AC is not starting. I think that there is problem in presostat - does anyone knows what are the signals from presostat, or how to understand is this the problem.

Klausc · Post by **Klausc** » 05 Jun 2008, 11:47

dumfree wrote:I have almost the same problem. I checked fuses, AC relay, compressor clutch - all is OK. ACC control module sends "AC request" to the ECC module, but AC is not starting. I think that there is problem in presostat - does anyone knows what are the signals from presostat, or how to understand is this the problem.

To check the pressostat, turn the AC on and cold. Then unplug the pressostat and short the wires by inserting a short wire into the + - slots of the plug. The compresssor should start, if not it is a fault somewhere else. do not run the compressor for long.
Did you check the r143a pressure? It needs to be above 17lbs to engage.

dumfree · Post by **dumfree** » 06 Jun 2008, 11:37

I checked the presostat in this way and there A/C don't starts.
The firs thing i checked was the R134A's pressure and it is OK.
I's looking that i'll have to visit local volvo dealer to read trouble codes and for repairing. There is some trouble codes stored in ACC control because when i switch off engine - the REC and ACC leds are blinking for about 20 seconds.

P.S. I'm with '98 S70