V50 AC : V50 air con problem.

[PLRich]

Hope someone can help.
I have a 2011/12 V50 D3 SE. Air con packed up 6 months ago. Had a new compressor, new hi pressure sensor and new gas. (No leak) A/C on off button goes from green to orange OK. No fault codes shown. Relay and all fuses good in both fuse boxes. 12v getting to relay. But I think it must be earth switched because when I short low side of relay to earth the a/c kicks in and I get cold air.
Basically garage has given up and the last diagnostics I have done myself. Now I am stuck.
Where does the low side of the relay go to? I don't have any circuits.
I've had this V50 from new. It's perfect condition and done over 200k miles. This believe it or not is the only fault I've ever had with it. (Apart from the windscreen wiper link arm)

Any suggestions greatly appreciated.

[IainG]

Hi
I think in Vida there is a function to activate the aircon, not sure if that can help. Will check with my Vida later.
If the function is there it might be able to prove the signal to the compressor and or clutch at least. Vida also measures the aircon temperatures but not sure if it will check the pressure/ switch?? If I get time later will have a look.

[PLRich]

Thanks.
A new pressure switch was fitted with no joy.
At the moment I have the AC running because I have the low side of the relay shorted to earth. But of course it's not controlled or regulated. It's just always on as if set to low.
The system must be switched to earth I suppose.

[IainG]

Hi
Just had a look and the only things I can find is a function to switch on/off the AC relay and also to monitor Evap temperature. Couldn't find anything else but there might be other fault finding tests??

[rkeegan]

Originally Posted by PLRich

Thanks.
A new pressure switch was fitted with no joy.
At the moment I have the AC running because I have the low side of the relay shorted to earth. But of course it's not controlled or regulated. It's just always on as if set to low.
The system must be switched to earth I suppose.

Not sure if you have resolved your problem but I had a similar issue on a 61 plate SE v50 D3. The garage couldn't find the fault either. I too ran with a wire connected from the relay via a switch to earth and switched the a/c on as and when it was needed. The problem turned out to be the low pressure switch which you appear to have replaced. I found the issue by disconnecting the wiring and putting a jump wire across the terminals of the disconnected plug this would make the A/C kick in. Might be worth doing this to check the new switch isn't faulty.
P.S. If you need more technical info about the system put "S40MY2005-Climate Control" into google and go for the Volvo technical document on the VOC site.