Ac blowing hot air


Why does my 1998 chevy s-10 blazer 4.3l blows hot air? The funny thing about it is that the compressor clutch is working so my guess is that their is freon in the system. What is the possible problem.


You may have enough gas pressure to keep the low pressure safety switch closed but not enough total gas weight to produce liquid in the receiver dryer. The best way to diagnosis is to throw a set of gauges on the high and low pressure taps and see what the system is doing.

One way to check the operation of the system without using the gauges, is to feel the suction line as close to the evaporator as you can get. If it feels cold and dewy, you may have a temperature blend door problem i.e. the AC is working but the internal controls are not letting the air pass through the evaporator.


Is it hot air or just ambient temp air. If the former, you might have a blend door or heater core valve stuck.


I do not have any gauges. Should I purchase gauges for this project? The blend door seems to be working fine. What else could it possibly be?


I had the same problem with my 2000 Blazer in 2003 right after I bought it. The compressor was only staying on 5 to 10 seconds at a time. One of the pressure switches had to be replaced under warranty (high or low I don’t remember).

Ed B.


I had a similar issue on my 89 Blazer - some idiot (3 guesses who that was) dropped a pen down the vent and it worked it’s way into a position where the blend door wouldn’t close properly.