2001 Blazer LT 4x4

On the way to work this morning with the heat, on it was only blowing air with no heat. It was semi-warm, not freezing nor hot.....temp outside was around 35 degree F

Usually the recirc button with the light on it is on or the "incoming air" button (for lack of a better name) light stays on when the heater (or A/C) is running. Now if I push one of those buttons it blinks around 3 to 5 times and then goes off.....Pushed the A/C button and lowered the temp and the A/C button with the light just blinks a few times and goes off also.....didnt seem to lower the temp when I ran the A/C for a few minutes either.

Any ideas?

 

The PCM will only command the a/c compressor on if the ambient temperature is above 35 degrees F.

The recirculation button will only stay lit if the mode is in one of the panel positions (recirc is not available in floor or defrost modes)

As for your heat...you either have a low coolant level or a pluggud up heater core...you need to first check your coolant level, and make any repairs needed, then back-flush your heater core.

 

If it still has Dex-Cool as a coolant andit looks "milky" and not "clear", your Dex-Cool is toast!Those small particles that has separated out of solution have clogged your heater core. Flush your system and back flush you heater core.

I filled mine with the new "global" coolant that will mix with Dex-Cool or the old "green" stuff.

 

Thanks guys.

I back-flushed the heater core, topped off the coolant, and it works great now......took 30-45 minutes only because it was dark out.