1998TA__1991RS

iTrader: (23)

2003 Silverado, originally a 4.8 4l60, now a 408/4l80. Manual AC controls. The AC compressor clutch will not kick on until you rev the truck up. I have checked the low pressure switch and it is grounding as it should. The pressure transducer is receiving 5 volts and putting out 2 which seems to be normal. I can manually control the ac clutch with efilive and everything works as it should. The compressor is not recieving voltage until you either rev the truck up or manually tell it to kick on with efilive. Once you rev the truck up the clutch kicks on and everything is fine until you either turn the ac or the truck off. Any other ideas that may be causing the issue? This truck also has an electric fan conversion. Thanks

TX Tahoe Z71

iTrader: (28)

Swap the relay with one you know works, like the fuel pump relay.

1998TA__1991RS

iTrader: (23)

already did that, that was actually the first thing i did

TX Tahoe Z71

iTrader: (28)

You hook a gauge up and check the pressure? That would be my next step. Harbor freight has some gauges for cheap.

1998TA__1991RS

iTrader: (23)

pressures are right where they should be.

Kemble

iTrader: (1)

Not sure if its even realted but I had a dodge cummins truck that you had to rev before the compressor would kick on. After the initial rev it worked flawlessly untill you shut the truck off. That one turned out to be the clutch on the compressor being wore out.

06murder

Yeah ac compressor may be going out... take the belt off and see of it move easy or kinda hard to move. If its hard to move get a new one

1998TA__1991RS

iTrader: (23)

i thought that also, but the compressor works fine when I command it through efilive

06murder

Have you swap relays yet? Have you tried swaping ac controls out yet?

nonnieselman

iTrader: (10)

My 2000 does wierd stuff like that. I just two foot it when im at a red light or stopped in gear. Bump it into neutral or park and the AC works fine. but not in gear at idle.