Have you checked the supply wires? I’ve had them go bad, at the plug, Also on my truck, one runs to the starter, for power, a break would cause it to kick out. If the expansion valve is bad, it should have showed up on gauges at shop, as unbalanced pressures. Unplugging the high pressure switch and jumping it would let it run with a bad expansion valve, Also will blow a line from high pressure, but not just to rule out high pressure as a cause. Assuming the high pressure switch is good. Another spot to check wiring is at the temp probe sensor in the evaporator, ( coil in dash) I’ve had those wires get broken, or loose on connections. Usual causes are either a fan/ pressure switch, bad connection or plugged expansion valve, causing high pressure. One valve on cab, and another in bunk. Either one plugged will cause high pressure.I would run a hot wire and a ground directly to compressor, to rule out a wiring or switch problem. If fuse was blown, why? Bad wire?
AC compressor wont engage
Discussion in 'Volvo Forum' started by DUNE-T, Mar 18, 2020.
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So last week on the way home I stop at Volvo in Toledo, get a new expansion valve and was going to get that relay, but two different part guys could not find anything and claimed that there are no relays in there.
Ok, I went home, dropped off truck at a shop and told them to also replace that hot/cold valve, since I had one laying around for ages.
Later that evening I picked up the truck, AC was working and I was happy as hell.
Today I went to my yard to work on my car, started the truck, turned on the AC just to make sure again that it works fine and started to do other things.
Well, came back to the truck 20 minutes later and #### thing is not working again! I wanted to pull my hair out.
Figured to check on that relay, thank you for pointing that there is a bolt under the speaker, I would have never thought of it. Took the panel out, there are two relays in there! I don't know why dealership could not find them in their schematics.
Switched them from left to right and the #### AC started to work!!!
The easy way to check if relay is bad, switch them from left to right. The right relay is connected to the CB radio power, where people usually connect their phone chargers. I plugged my phone and it started to change intermittently, second on, second off.
Thank you, @nasriza ! Not too many people know these older Volvos and you just saved me from losing my mind!
Rideandrepair Thanks this. -
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