1987 Iroc z28 5.7 tpi. Had no cooling on car last fall and took to local chevy DEALER to get it fixed. Already had it switched to 134. They replaced the compressor and 35974 ac switch. Worked fine after this spring the compressor wont even engage. Any thoughts would be helpful when I take it back in for more service. Is the outside temp have anything to do with engagement since it has only gotten to 60 so far this year and if thats the case wont it engage anyway on the defrost setting?

 

Defrost shouldn't be affected unless you're trying to blow cold air.

 

Yes just trying to get the compressor to engage. I know on my pickup the compressor will cycle at 10 below when defrost is on. If all the freon leaked out over winter storage should the compressor run constantly or not engage at all?

 

Not at all.

 

What I was thinking whatever happened to sightglasses at least you had a clue what was in system!