a/c only works at idle
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Record Breaker
Joined: Mar 2009
Posts: 1,430
Likes: 2
From: WV
I know on mine, as long as the compressor is engaged the pressure reads about 35 psi which is supposed to be about spot on. But when you apply gas the clutch disengages the compressor and pressure spikes to the high side. It happens so quick though that I havent been able to decide which is taking place first, is the pressure spiking causing the compressor to shut off, or if its the compressor shutting off that is making the pressure spike. And if its the later then why is it kicking off?
I know on my last truck I had a issue with it staying on and i ended up putting a jumper wire on the plug coming out of the top of the dryer and that worked for a while. But I would like to fix this correctly.
It sounds like our issues are caused by the same problem. I only have a gauge to hook up to the low pressure side. I actually have a video of it posted in my thread. What would I be looking for on the high side?
I know on my last truck I had a issue with it staying on and i ended up putting a jumper wire on the plug coming out of the top of the dryer and that worked for a while. But I would like to fix this correctly.
It sounds like our issues are caused by the same problem. I only have a gauge to hook up to the low pressure side. I actually have a video of it posted in my thread. What would I be looking for on the high side?
Captain
Joined: May 2011
Posts: 652
Likes: 0
From: Central Florida
I would borrow a gauge set and make sure the high side pressures aren't spiking for some reason and the high side switch isn't kicking it off like it's supposed to. After that is verified you could try to bypass the high side switch and see if it works properly. Then you'd know the switch was bad. From what I've read on here you don't have to evac the system to replace the switch on these trucks. Some vehicles you do, some you don't.
Rookie
Joined: Apr 2011
Posts: 67
Likes: 0
From: Edmonton, Alberta
Where is this said high pressure switch? I'm currently trouble shooting mine. I jumped the switch, bled pressure, checked relays and fuses and all good. Cant get the compressor to engage.....wtf?
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Record Breaker
Joined: Mar 2009
Posts: 1,430
Likes: 2
From: WV
Well I jumped the high switch today and it did nothing still cycled off with any rpm jump. I then jumped the cycle switch and it stayed on but the ac is only about 56 coming out the vents at 2000 rpm. It must be low on freon. I talked to the a/c shop today they told me that an a/c system in a car or truck will aways have some weep age around the seal at the compressor. He said that with it setting that the seal started to dry and when I started the a/c back up that it let just a small bit of freon to make it short cycle. Its $65 for the a/c service which they will recover all freon check for leaks and put back all freon that was in the system. Plus the cost of any freon needing to be added. So not to bad.
Record Breaker
Joined: Dec 2008
Posts: 1,585
Likes: 0
Well I jumped the high switch today and it did nothing still cycled off with any rpm jump. I then jumped the cycle switch and it stayed on but the ac is only about 56 coming out the vents at 2000 rpm. It must be low on freon. I talked to the a/c shop today they told me that an a/c system in a car or truck will aways have some weep age around the seal at the compressor. He said that with it setting that the seal started to dry and when I started the a/c back up that it let just a small bit of freon to make it short cycle. Its $65 for the a/c service which they will recover all freon check for leaks and put back all freon that was in the system. Plus the cost of any freon needing to be added. So not to bad.