2nd Gen Non-Engine/Transmission A/C compressor won't come on

[fortunate1]

A few weeks ago, I had to drive back to my tree-ravaged house through 2-3 feet of salt water tidal surge. Yes, my truck got "Isabel-ed"; a tree limb landed on it and broke the windshield. All fluids are fine, and only the horns seemed to suffer electrically, so far. But yesterday I wanted to use the A/C to help defog the new windshield on a rainy day. No good. The fan worked fine, but the compressor would not come on when the fan switch was turned over to the left/blue settings. I got underneath and tapped the front of the clutch and the compressor body while the engine was running to see if that would free it up. No good. The belt pulley spins just fine, but the clutch won't engage to spin the compressor. Any ideas? Insurance will probably pay for a new compressor, but I thought I'd try to fix it first.

 

[DavidC]

Did you check all fuses? I do not know exactly where it is on your truck but running in water and if the compressor cycled that could be your problem. You could unplug the compressor, turn the system on and check for 12VDC at the plug.



Dave

 

[bmoeller]

When the tree kissed it, did it do any damage under the hood that may have caused a freon leak?



There are high and low pressure switchs in series that prevent the clutch from engaging if the freon is low or the psi is too high. Keeps the compressor from siezing from low/no freon (and oil) or from excessive psi and blowing out a seal or something else.



Compressor clutch shot, or broken wires to it?

 

[SRadke]

The compressor clutch and horn are on the same fuse. That's probably where your problem is.

-Scott

 

[fortunate1]

Thanks for the replies. I didn't mention it in the original post, but I did check the fuses/relay first. They're all fine. I think the salt water did it in.

 

[GTX]

I just had a similar problem on my 99. There is a hose that mounts on the compressor and goes up past the intercooler tube and kind of under the oil filter. Part of it is aluminum and mine had gotten against the intercooler tube and rubbed a hole in it. Dealer said it was a common problem. When changing the oil filter, it gets moved if you are not careful enough. New hose has a plastic cover to prevent the problem.

 

[rashwor]

Could be the PCM...

Before you spend a bunch on a compressor you don't need, do some testing. Mine quit working the other day. Compressor simply would not come on just like yours.



Turned out to be that I had a short in the wire that goes from the PCM to the relay that triggers the compressor clutch to engage. Fried my PCM. Local mechanic fixed the shorted wire and replaced the PCM with a reman. Been working fine ever since.



Do a lot of checking... make sure the compressor clutch is getting fire before you assume... .