My 1990 XJ's air conditioning quit working. It appears my AC clutch is not engaging the compressor.

I checked the low pressure switch - Okay
I checked the relay - Okay
I ran power directly to the clutch - Engaged

So... where do I go from here?

How do I test the AC control unit to see if it is working correctly and telling the relay to engage the clutch?

What else am I missing that I need to test?

Any advise would be greatly appreciated as it has been about 95 degrees here lately. Thanks!

 

If you are low on freon that will cause it not to engage. Just something to check.

 

My freon is fully charged, but I bypassed the low pressure switch just to make sure that was not the problem...

 

I had a similar problem. Did all the same checks. Had all the same results.

But I recharged it anyway and it worked fine from then on.

Go figure! But it did the trick. Worth the $30 to try.