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HDGENE, Ford Senior Master/Diesel/Trans
Category: Ford
Satisfied Customers: 5493
Experience:  25 years Auto experience, Ford ,GM, Chrysler, Asian & European
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F150: I am having AC issues, 2004 F150

Customer Question

I am having AC issues, 2004 F150
Submitted: 1 year ago.
Category: Ford
Expert:  HDGENE replied 1 year ago.
Hello, the ac is cycling off at idle or while driving? what are the pressures when the ac shuts down? it blows cold and drops off or not at all?
Customer: replied 1 year ago.
The AC definitely cycles off while driving, it blows cold then drops off. Sometimes it will come back and stay on for a lengthy time. If it will not come back, I shut it of while driving, and then start it again in 15 or 20 minutes. It will then blow cold. When it has been off and I have come home, I have let it idle and it will not come back on. Again if I shut it off for a few minutes, it will then blow cold. I have not let it idle long enough to see if it drops while idling. I do not have a reading of the pressures when it shuts down, I have been trying to get that. However when it is blowing cold, I was told by the service guy the pressures where good. Hope this helps.
Customer: replied 1 year ago.
I will add that I have replaced the comp clutch cut out switch and the high side cut out switch as well. Coolant levels are good
Expert:  HDGENE replied 1 year ago.
Well if the ac cuts out over time driving and it takes a while for it to come back on either there is something going on with the clutch coil/compressor you said you replaced only the clutch not the complete compressor? Really need to know what the ac pressures are while its b lowing cold and when it shuts down. Its possible you have a bad fan clutch not moving around enough air which is possible causing the high side pressure to ramp up and the high side pressure switch cuts off the compressor. Need to see if the compressor clutch is getting power and ground when the clutch wont engage. Assuming you have the proper amount of refrigerant thats the areas id look into, possible bad fan clutch which you can tell be revving the engine up should move a lot of air away from the radiator and ac condensor or possibly a bad ac clutch relay overheating and shutting down the ac system
Customer: replied 1 year ago.
No I did not replace the compressor clutch, I replaced the "A/C Comp Clutch Cycling Pressure Switch" and the high side pressure switch. I have not done anything to the compressor. The fan clutch and radiator are less than a year old. Incidentally, this F150 has over 350,000 miles on it. I use it for my business, and I have never had to have the AC system serviced. Has worked fine until recently.
What should the AC pressures be when blowing cold? What pressures would I expect to see when it drops off?
If they are not what you expect them to me when it drops off, what may be the cause?
Thank you.
Expert:  HDGENE replied 1 year ago.
Low side at idle approx 30-40 psi, high side 200-250 psi roughly. Also check the area in between the ac condensor and the radiator for being clogged up with debris restricting air flow. You might have a worn out ac compressor with that many mile son it being original
Customer: replied 1 year ago.
I will double check the pressures both when idling and blowing cold and try to catch the pressures when it begins to go away. I can tell you that when the cold goes away, the compressor has stopped running. The other day is started to go away as I came home. I left engine idle and looked at the compressor, it was not running. The clutch was not engaged. I pressed the AC button on the dash and it started, and blew cold air. Something is making the compressor turn off randomly.
Expert:  HDGENE replied 1 year ago.
Right, if the switch is on and has full charge of refrigerant the compressor should come on unless either the compressor clutch coil is weak, not getting power to it from a cycling switch or overheating ac clutch relay.
Customer: replied 1 year ago.
What do you mean by the cycling switch. Is that the same as the "A/C Compressor Clutch Cycling Pressure Switch"? If so I replaced that. Is there another relay I need to be looking at?
Expert:  HDGENE replied 1 year ago.
Yes the low pressure cycling switch and/or the high pressure cut off switch
Customer: replied 1 year ago.
Is there a relay for the clutch compressor, if so where would it be located?