2002 isuzu trooper / bighorn / monterey
A/C works perfectly and is nice and cold from cold engine start and will stay working all day long, as long as the vehicle is not turned off.
It will intermittently start working sometimes after hot start but only rarely.
I have done some basic diagnostics:
When it is working the a/c clutch is working correctly and there is a bright 12v from my test light to the a/c pump wire.
When it is not the clutch is not working properly eg the pump is not spinning, when I put a test light on the wire there is only a very faint glow.
As soon as I leave it to cool down the a/c works fine again.
Any ideas would be much appreciated. -thanks.