AC problems

2002 Trailblazer, AC worked this morning and on way home is not blowing cold air. What should I check or have checked first?

Make sure the temp control is on cold. Obvious, I know, but it’s an easy thing to miss.

Otherwise it is probably something you’ll want to have checked by a mechanic. You may have a refrigerant leak. If you’re lucky it’ll just be a loose valve, and all you’ll just have to pay for new refrigerant.


It could be anything, but because of the abruptness of cooling loss I’d assume something electrical. The compressor clutch circuit. Start the engine, turn the A/C to MAX COOL, open the windows, then look under the hood at the compressor. The whole pulley should be turning. If the center half is stationary, then the clutch isn’t engaging. Take it to a shop to be checked for proper charge before diagnosing the compressor clutch circuit. If you know how to troubleshoot an electrical circuit then go ahead and try it yourself.


I saw some information on 2002 Trailblazer EXT, I don’t know if that is your model?

The info said, the original ac charge spec label under the hood was not correct. If you ever had your system worked on, that has probably been corrected?

If not, that spec could cause AC performance problems. If you have somebody work on your system, you might mention that. The bulletin is 02-01-39-006.

As far as bulletins in the hvac section for this vehicle, there were a bunch. I didn’t look at the other bulletins, that one just caught my attention. It may not apply to your model.

try this:

when you are driving and the ac stops working, pull over (when/where safe) stop the car, turn off the key, make sure the cool switch is all the way to cool. wait a minute, then restart.

Just curious, when the ac works, does it stop working when you turn the temp control to LESS cool?

if this makes the ac cool again, the problem is the diverter valve which shuts off the hot water to the ac. sometimes when they jam up, they jam open, so the hot water over whelms the ac capability to cool.

i dont recommend this to be repaired by you, since there are several variables which could be problems too.

take it to an AC repair shop. ask friends for a recommendation. or look up on this web pages home page, under the mechanics files, by zip code.