Aux fan cycling on an off
01-21-2011, 10:07 AM
#1
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Year: 99
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Aux fan cycling on an off
Hi, my electric fan has recently started cycling on an off when in defrost mode. Where should I look. Also antone know where I can get a factory service manual. Thanks
01-21-2011, 10:25 AM
#2
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Year: 2000
Model: Cherokee
Engine: 4.0
Someone please correct me if I'm wrong, but I was under the impression that the electric fan is supposed to cycle on/off when the A/C/defrost is on?
01-21-2011, 10:28 AM
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Year: 1989 xj sport 2dr
Model: Cherokee
Engine: 12 hole bosch Injectors
sound like its working correctly to me to check turn the ac on see if it stays on assuming the ac works
01-21-2011, 10:32 AM
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Year: 1985 shell
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Engine: 1996 6 cylinder Briggs & Stratton
Correct- the system cycles on and off with the defrost to keep the AC system lubricated and prevent the seals in the AC system from drying out!
01-21-2011, 10:40 AM
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Year: 1995
Model: Cherokee
Engine: 4.0 High Outout I6
Originally Posted by joes99xj
When I say that it cycles on and off I mean every 2-3 seconds when in defrost. Thats not normal.
Other than that sounds normal to me
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01-21-2011, 10:52 AM
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01-21-2011, 12:40 PM
#9
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Year: 1995
Model: Grand Cherokee
Engine: 4.0L AWD
In most vehicles I have owned with A/C, the defrost is actually using the A/C... hence why it will cycle and why the electric fan on the radiator will cycle.
01-21-2011, 12:58 PM
#10
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Year: 2004
Model: Grand Cherokee
Engine: 4.0L
Mine does the same thing. Many cars do it. You just notice it more because the fan sounds a little louder than it does on other vehicles.
01-21-2011, 01:37 PM
#11
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I understand the fans operation however it just started cycling rapidly. Engine cold 40 degrees outside the fan is cycling on an off it only runs for a few seconds then back on. Its like someone flicking a switch.
01-21-2011, 01:42 PM
#12
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i was wondering if you meant it was on for like 2 sec, then off for 2, then on for 2, etc... cause that aint right... sensors, relays, fuses, grounding... all good things to check.
01-21-2011, 01:45 PM
#13
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normally if it is cycling on and off this quickly, it's due to there not being enough pressure in the a/c system. The low pressure switch activates to prevent damage to the compressor. You need an a/c recharge.
01-21-2011, 02:00 PM
#14
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Year: 99
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good call! there was an article in Jp Mag. like 2 months ago about doing a really cost effective AC recharge. it wasnt free, but compared to what a shop would charge, it was a steal.