Well I needed a new DD/Winter car and came across a Volvo V70 for a great price. It's a 1998 V70 NA, FWD. Fully optioned (I'd assume).

Car runs great, just a few issues.

The AC didn't work, and I knew that coming in, it was really low on freon, and I evacuated and filled it to the proper amount. Still nothing, found the wire to compressor was grounding and fixed it. Still nothing. If I ground the relay myself, it kicks the compressor and blows cold. So judging by the wiring diagram I found, does this mean the ECU isn't telling the compressor to kick on? I came across an ECU cheap and just picked it up, can I swap this ECU with no issues? Also, the ECU I picked up came with a Bosch unit, then another Japanese unit. Both are marked 1998 V70.

Only other small thing is it has a long crank on startup, or I have to crank it twice. But it fires up with no issues, runs smooth, and get's great fuel mileage when it's going. Just curious what would be causing it. It acts like a fuel pressure regulator would in a GM vehicle, but I'm new to these.

Any help would be greatly appreciated. Thanks guys!

 

If you ground the relay and the AC works, then the relay is defective.
Get new relay from dealer.
You do NOT need a new ECU!

 

I already tried a new relay. I'm saying I put a ground to the compressor like the relay should. I might try another relay, but I doubt that's it.

 

Then search "Volvo Grounding Points" here and on Google.