96 escort a/c

[novice mech]

Worked 2 days ago, recently charged then the relay clicks every ten or so seconds and the compressor won't engage. So I replaced the relay, which was only a month old, and the new one does the same thing.....Anyone have any ideas?

[Davescort97]

The relay is going off and on because of an overload. Check the wiring going to the AC clutch. The clutch on the compressor could be grounding out causing the relay to go on and off. Don't know how to check it. Downstream from the AC relay is the cycling switch for the compressor. Are you sure it's not the cycling switch that is causing the trouble? Pull the wiring connector to the cycling switch on the reciever/dryer. bypass the switch with a wire or paper clip. If the clutch operates without going on or off the problem is with the cycling switch which is designed to cut the current from the the AC clutch if the freon charge is too low. I know you said that the charge is okay, but a low freon charge would make the switch go off below 24 psi on the pressure.

[tripletdaddy]

Uh uh.

It really doesn't help that AC pressures are counterintuitive. It really messes with your head and gives you a headache.

The clutch cycling switch turns OFF the clutch circuit at 25 psi while cycling, meaning, it will cut-out as the pressure DECREASES to 25 psi. Also, the switch won't let the clutch come ON until the pressure is high enough, irregardless if at first startup or during normal operation. The cut-in pressure is 45 psi and is reached with an ASCENDING pressure during normal cycling. But, the switch will come on at any pressure higher than the 45psi cut-in pressure like when you first turn on the ac.

Any component that you suspect is grounding out a circuit, like the suggested clutch coil, can be simply tested with a continuity test meter. Disconnect all wiring, then probe each connector pin on the component while touching the other probe to the component's exterior and then to the battery ground. If you have little or no resistance, there's your short to ground and the bad part.

If you want to know more about this, I just put together a much longer discussion on this in the Taurus Forum. Only because of personal need and professional background, do I know any of this. The specifics came from Ford's SM and Haynes for comparison.

http://http://www.automotiveforums.c...3&goto=newpost

BTW, Davescort97, I'm not into turf wars or offending anyone, but I felt I should clarify on the pressure settings. Everything else sounded good.

[Davescort97]

Tripletdaddy--No offense taken, glad you could help out here. My knowledge about AC is limited. I posted because the thread was 2 days old and no one had replied to it. Thanks TD

[tripletdaddy]

Since I don't use this information often, I have to reteach myself whenever I troubleshoot or explain the confusing operation of an ac system/refrigeration cycle just to be sure I've got it right!?!

I like to err on the side of caution, especially with strangers, when it comes to expressing opposing statements after encountering folks who adamantly believe they are right, and they are more interested in being right than what is really right. My attitude isn't to be right, it's to know the right thing and to help others learn the right thing. Living in ignorance is not empowering, it may give one false empowerment, but only with real and correct knowledge will one be fully empowered.

Whatever all of that is supposed to mean in our present state of relativism.

[novice mech]

Thanks for the info fellas. I hope to be able to help someone else as much you have helped me.

[tripletdaddy]

If you're close to Virginia, I have a bunch of auto maintenance that I need catching up on!