Air Conditioning Issue

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Jun 9, 2005 | 05:35 PM

chickenboy129

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Air Conditioning Issue

I've got a 2001 F150 4.2 manual with about 79K on it. I'm having an issue with the AC. For the most part, the AC doesn't run at idle. The clutch just kicks on and back off. When I'm reving the motor above 2K (moving or not) the AC works fine.
Any ideas on what could be causing this issue?

Jun 9, 2005 | 08:18 PM

chickenboy129

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I found that it's the high pressure switch. I can hear the switch cycling. I can understand if there is a high pressure issue, but why would it be only at low RPMs.

Jun 9, 2005 | 08:32 PM

BrianA

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From: Trussville, Alabama

Not sure, unless the slower turning compressor is not able to keep enough pressure to satisfy the low-pressure switch.
I had the same thing happen on a previously owned Expedition.

Jun 10, 2005 | 05:37 PM

NHRstein

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From: Manchester, NH

Hey something I do know about, yay!!

Anyway when you rev your engine your cooling fans rev with it, creating more air flow through the condensor. Try cleaning your condensor, a dirty condensor is usually the culprit on almost every high pressure issue in the HVAC world.

//John

Jun 11, 2005 | 11:55 AM

chickenboy129

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NHRStein...you have the accepted answer. I checked the condensor and it was clean, but it got me thinking. I run electric fans. I hadn't noticed before, but they weren't cutting on when the AC Compressor did. I found I had a bad connection on the lead from the fan relay to the AC Compressor. So it was the lack of airflow over the condensor that was causing the issue after all.
Thanks for everyone's help.