I just recently got TTS Datamaster EE for my car (1994 Chevy Camaro Z-28) and was using it while driving around in my car the other day. I noticed that when I put the HVAC control in bilevel mode with the heat control on full heat that my AC compressor kicks in. I have noticed on occasion in the winter time with the heat on that the AC compressor kicks on and off even with the heat cranked all the way up. It seems like it only hits an AC request when it is on the AC, MAX, and bilevel settings, regardless of the temperature setting. Granted the first two should kick the compressor on, but what about bilevel? Might I have a vaccum leak or is it supposed to work that way?

Also, I have noticed that I don't get very warm air coming out of the heater when it is on. It doesn't matter what the HVAC control is set it, whether it be bilevel, floor, upper or defrost, it spits out lukewarm/cold air. I have been thinking that it was a clogged heater core, but would there be any other possibilities? What vaccum lines would I need to check and how would I check them? Could the AC compressor kicking on cause me to have colder air output?

Thanks in advance.

 

Bi-level also is part of the a/c mode, so it will cause the compressor to come on. It will have a slight effect on the temperature of the air at the same temp setting vs. when the compressor is not on.

Your poor heat is probably a partially clogged heater core. All you have to do is remove the hoses at the water pump and flush both ways using a garden hose. Just keep any water off the optispark.

 

My 95 Z28 Convert has never blown really hot air since it was new. I drive 40 miles to work and sometimes never turn the heat and blower off "high" the whole way, this is in 20deg or so weather..
Ron