So I've been having issues with the A/C since my motor/big turbo build (battery was relocated to the trunk if that answers anything). But basically the clutch is not spinning at all with the A/C button on (light is steady green). Put 12v directly to it and it spins right up, no problems. The line pressure tested good...everything seems normal.

However, there is one thing I am confused by. Which wire provides power to the compressor? From what I can see, there is one black/white white from the outside that comes into the white side of the two-pin connector. We tested that and saw that it was a ground. So if that wire is a ground, where is the power wire?

Anybody???

Thanks in advance...

 

Not sure I really have an answer to your question directly, but the compressor operates with a pressure switch. If it's spinning fine with power to it, and not at all when the car is running I have 2 suggestions.

1. Check the AC system pressure.
2. Consider that the clutch system operates via an electromagnet. Electromagnets and their functionality are obviously directly influenced by electricity. If the system doesn't use 12v stock to power the magnets (it may, this is the part I'm not sure about), then the reason the clutch may have spun with 12v, but not (insert less voltage here) is because you effectively provided more Gauss to the magnetic field, and this was enough to activate it.

Many people find that after a few years, it is necessary to re-shim their clutch system on their AC, which again... is essentially slimming that gap down, so that it is again, within the necessary field of the electromagnetic system.

Evo's seem to have a very sensitive electrical system, and while this problem could be coincidental, I typically always like to begin by assuming if something was working, and then you did something, there must be some logical reason for why it isn't working now, and they're usually related.

As such, by relocating the battery, it is possible that you lowered the total voltage of the entire electrical system just enough that now the compressors electromagnet may not produce enough Gauss to activate that clutch.

So as I said. Start simple, go to complex.
1. Check AC pressures.
2. Check clutch gap, and adjust to within spec.

If none of that works. Drive the car off a cliff, escaping brilliantly at the last second, and claim it on insurance. It's win/win really.

Good luck.

 

First step is to connect some a/c gauges and check pressures. If the pressures are low the a/c compressor will not come on even though you still may have the light on. while your at it check for any obvious leaks in the system. If your able to, evacuate the system and check how much came out.