I have a 1998 v70 that the ac is not working. I do not have a ground at the ac relay, it does have a full charge and I jump the low pressure switch. The light is on the control panel. Does anyone know where this ground signal comes from.

 

Well, there looks to be 3 relays controlling different things, one is for the a/c clutch, the others are for grounded through the CCM and ECM it looks like. Not sure which relay your checking or if you have Electronic or manual climate control.

 

Its the relay for the clutch, I can jump 30 and 87 and the compressor works but no ground signal at 87/85. It has a manual system.
Thanks

 

87 wont have a signal, so there is no problem there. PIN 86 should recieve power from a fuse, which should be ok, so 85 is most likely your problem which is ground from ECM and one pressure sensor and one pressostat (switch) are part of that, but you may want to pull the ecm fuse first and/or disconnect the battery, and wait 15 minutes and see if that helps. ECM codes will prevent operation, but i may be the CCM. Good luck

 

Disconnected the battery and now is working. I will see how long, I would think that the fault is still there. Do you think this means that the control unit is good?
Thanks