My AC Compressor clutch is engaging and disengaging continually, approximately 20 times a minute. This is happening when my AC is turned off. Whats going on??? When I turn on my AC, the clutch stays engaged and blows cold air.

Mr.B

 

what year? Is it only when you have the defrost on? I was once told the compressor is designed to cycle like your describing while the defroster is active. Reason being to keep the compressor from siezing due to prolonged periods of non use during the winter months.

 

Yep, it's designed to cycle on defrost, but 20 times a minute sounds excessive.

 

I have a 93 XLT and the only way the compressor does not cycle is when I have it in the vent position or in the off position(in the owners manual). Other wise it will cycle even if you have the heater on unless it is in one of the above positions.

 

I had a similar problem on my '85. I just needed a couple of pounds of refrigerant in the system. The compressor clutch stopped turning on and off afterwards.

good luck.

 

[updated:LAST EDITED ON 27-Nov-01 AT 01:44 PM (EST)]My Bronco is a 92. My defrost was on HIGH at the time I discovered the cycling. I did not here it cycling today and I had the heater on low. When it was cycling, I opened up the hood to find out whats clicking and saw it cycle on and off a few times within a minuite, is that normal?

Mr. B

 

Yep....that is exactly what mine does. Thats what made me check out my controls. put it on vent and and leave the heater on and the cycling should stop. Maybe someone out there can explain why the compressor cycles in defrost mode.

 

Most vehicles I have owned would kick on the compressor when the defrost was turned on. Does it have anything to do with removing humidity from the inside of the vehicle? Someone out there knows this I am sure.

Jason

 

I'm no a/c mechanic, but I think it does..... just consider how much more effective it is to defog your windshield on a rainy and damp summer evening using the a/c. Although vehicles without a/c obviously have defrosters, I believe those with it make use of the compressor to help out the process (all that I've ever owned had the compressor kick on with the defroster).

 

Wow, That all makes sense to me. Thank you guys! I love working on my Bronco, However, Ive always shyed away from AC systems. I almost brought it to a AC mechanic who surly would have convinced me I needed a new Compressor and of course the freon upgrade. Thank God (Payne) for this message board!

 

While restorit is correct, that is not the entire story. The defroster uses the A/C dryer to help get the moisture off the windshield, but also exercises the A/C compressor during the winter to help the oil circulate and keep the seals from drying out.

Aaron D.