A/C Compressor running constantly on my '99 hoe

[willie1280]

Had this issue since i bought the truck. Just had the compressor replaced because it went bad and was hoping the new compressor would solve the issue but it didn't.

Mechanic suggested i take it to a dealership and have the computer reprogramed. Is that really my only option? And what does something like that cost?

thanks in advance

Matt

 

[SunlitComet]

first off while it is running constantly do it get really cold in the cab or does it seem like it is just keeping up? If it is really really cold the you cycling switch on the accumulator might be defective. If is just putting out enough cold air to be comfortable then you are looking at a low refrigerant charge or moisture contamination. You do not need your computer reprogrammed as far as I am concerned. The compressors on 99 does not use a variable orifice system that might need a computer controller. Perhaps there are some other details you can include. Like maybe system cycles as it should but the SUV acts like you have the a/c switch turn on all the time?

 

[gpracer1]

I dont understand the question.....are you saying that if you start the truck with the AC off , the compressor is on anyway?

 

[willie1280]

Well i will have to let you know about how cold it gets since I just got the new compressor in today, so this is the first time with air in 2 years. They checked everything they could and found no leaks and only a bad compressor. They recharged the system as well. I believe he said all the "valves" were working properly for the low/high pressure system...not sure what that means since i am no guru in the a/c dept.

The compressor runs constantly from the time the engine starts. The only way to stop it is to disconnect it at the top of the compressor with the little 2 wire plug. He said not to disconnect it since that would allow the oil to drain from the unit thus resulting in another bad compressor.

 

[SunlitComet]

First never use that guy again. Please. He is full of it. Second pull your a/c and blower fuses and see if it still stays on.

 

[willie1280]

I pulled the rear hvac fuse and the heat/ac fuse and the compressor stayed running.

Also on way home i ran the ac to see how the temp was. I wouldnt say it was freezing but i also wouldnt say it was playing catch up.

Also noticed and is probably unrelated but the air comes out of the defrost vents up by the windshield when on any zone setting even if not defrost. Its almost non existent on passanger side but somewhat strong on drive side...must be a flap notredirecting all the way?

 

[SunlitComet]

Pull the relay for the clutch next.

---------- Post added at 05:35 PM ---------- Previous post was at 05:21 PM ----------

And after your truck is started put the starter relay in place of the a/c relay but DO NOT put the original ac relay in the starter socket in case it is jammed closed.

 

[willie1280]

Where is the clutch relay and starter relay?

So i am going to pull the clutch relay, start the truck, check to see if compressor is turning, if it is then i will stick the starter relay in teh ac relay slot and recheck the compressor?

 

[SunlitComet]

Left side near firewall with a cover on it.
Yes

 

[willie1280]

Oh you mean the 2 silver relays in the fuse panel.

Which one is which?