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A/C Clutch Cycling ?

H

Hylander

NAXJA Forum User
Location
Texas
When I run my Heater, my A/C pump cycles on and off about every 10 seconds.
Is this normal ? If so, Why ?
Also; can I just unplug the A/C pump so it won't come on and off, or will that damage something.
Sometimes when it cycles on, my belt squeals.
I know my belt is tight, maybe to tight from trying to stop the Squeling.
 
Not sure what year XJ you have, but it's normal to cycle the a/c compressor while on 'Defrost' mode, which takes the moisture out of the air, but not usually while on 'Heater' mode. That's the way my 2000 works, as well as all of my other cars. You could unplug the wire going to the a/c clutch to keep that from happening, but obviously that would make your defroster (and a/c) much less effective! You might have a fuse or relay for the a/c clutch as well that you could pull out for the same result.

Good luck!

Jim
 
X2 on what XJ4Trails said. Also, if your belt is too tight and still squeals, try some belt dressing on it - if that doesn't work, put a new belt on it. Did you use a tension gauge on the belt or the "twist it/push on it" trick? The 4.0 belt tension is really high compared to a lot of other vehicles, you should use a gauge.
 
You want the A/C compressor to get used year round anyway. They are prone to have problems if they sit long periods without running.
 
The AC clutch on my 98 XJ only works sometimes and the cycling on and off during the defrost cycle was driving me crazy so I just unplugged the low pressure switch. This is located up near the hood on the passenger side and it just unplugs. This stopped the AC compressor from trying to cycle and also stopped the electric fan from coming on.....I live in Oregon so I don't need 2 fans during the winter. What really bothered me was when the electric fan kicked on the dash lights would dim momentarily. I know its a minor gripe but it seemed like every time I looked down at the dash while driving I was noticing a flicker.
 
According to the FSM, if the compressor cycles on and off more than 10 times in one minute then you probably have a low refrigerant system charge, meaning you probably have a leak or you just need to have it recharged.
 
The AC is supposed to cycle on and off when set to Defrost. Otherwise, you'll be blowing warm damp air across a cold surface, which is what causes condensation...

To the OP, are you sure it's coming on when set to Heat, and not Defrost?
 
It is on Defrost that it is cycling on and off.
It drives me nuts and makes the belt squel
I think I will unplug it and see how the Defrost works
 
Having been in your position, I recommend inspecting the belt, replacing it if need be, and buying a Krikit II to check the belt tension. While you've got the belt off, spin all the pulleys by hand to see that they all spin freely, don't make a racket, etc. If everything's good, you don't have the belt tension right.
 
hubs97xj said:
Having been in your position, I recommend inspecting the belt, replacing it if need be, and buying a Krikit II to check the belt tension. While you've got the belt off, spin all the pulleys by hand to see that they all spin freely, don't make a racket, etc. If everything's good, you don't have the belt tension right.
Click to expand...

Get a do-it-yourself recharge kit from Wally-Mart and see if that fixes the low-charge symptoms. Possible cheap-now repair to what is an expensive component system.
 
I've read on here that 5 cycles a minute is normal. My AC has always been cold, and the compressor runs 10 seconds, off 5, and so on. My squealing was cured with a good belt and the right tension. :dunno:
 
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