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Discussion Starter · #1 ·
2001 TJ 4.0 AC doesn’t blow cold air. Has Freon in it, and clutch engages and disengages about every 5 seconds. I’ve read that the clutch engaging and disengaging is normal. I unplugged the low pressure switch and the clutch stopped all together... I don’t want to replace un necessary parts. Can someone well versed in AC on Jeeps please advise.
 

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2000 Jeep Wrangler Sahara 4.0L 5spd Money pit Green
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395 Posts
Possibly low on Freon (short cycling) check your pressures.
 

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Sounds low on pressure or possibly a bad low or high pressure switch. I just worked on a '97 with the same problem and it was low refrigerant.

You need to hook up some AC gauges and look at the pressure.

Just so you know how this works electrically, or at least the '97 is that when you move the AC control to on, that sends a voltage to the PCM on one pin. The wire also splits off and goes to both of the pressure switches. One is high pressure switch. This one remains closes and opens if pressure gets too high. It's on the high side of the refrigerant circle. The second is that wire goes through the low pressure switch. It remains closed unless the pressure gets to low. Then the switch opens and breaks the circuit. This wire goes on the PCM through another pin. The PCM then can track if AC is requested and if it's allowed. If have a scan tool that shows live data you can see both PIDS.

The cycling that I had which sounds like yours, is the pressure is low but not low enough to open the low side pressure switch. When you turn the AC on, turns the compressor. But that suction from the compressor drops the low side pressure too much with opens the switch and the PCM then knows to shut off the compressor. Pressure goes back up cause the compressor is not running. Low side pressure switch closes and the cycle starts again.

You may have another problem but you need a set of AC gauges to see.
 
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