Ac compressor clutch wont engage

[fbaurley]

On a recently acquired 99 jeep cherokee we cannot ge the AC clutch to engage. At first I thought it was possibly due to low refrigerant or at least on the recharge kit I have it sounded like there has to be a minimuim pressure to activate a sensor so the clutch will engage. Well i added enough 134A to get it up to pressure, which required very little, and still the clutch wont engage. I checked all the fuses and they are good, any ideas? It kinda sounds like a switch to me.

 

[Lnwing]

I'm at the same place as you while trying to get the air conditioner working in my Massey tractor. If I use a jumper to the compressor clutch, it engages and blows cold air, but that's the only way it works.

What are we missing?

 

[CSnyder]

my 99 Jeep did the same thing... changed out the switch on the compressor and that fixed it proper... . hope that helps, Chris

 

[KBennett]

There may be a dead relay under the hood that should be sending the signal.

Do you have a way to check the voltage at the clutch? Start at the clutch and work your way back, including the ground.