Any tune related reason A/C would stop working?

Like the title says, is there any reason that my A/C would stop working when I have a MAF only tune installed? Refrigerant is full and I'm pretty sure it worked fine a few weeks ago when I was tuning the VE table. I'm in the process of fine tuning injector timing and MAF curve now and all of a sudden my A/C just blows hot air. The car is a 06' Envoy, which is known for having an a55 load of actuators and blend doors to deal with, so it could very well be one or all of them, but before I started tearing into those I wanted to make sure there wasn't something I was missing in tune related that would lead to disabling the A/C.

It's a pretty basic 5.3 setup; Chopacabra cam, milled 799's (.025 about 11:1) and long tubes. It seems to idle and run fine and the PCM voltage appears to be good, so I don't think its poor idle quality kicking it off.


I added the tune file and a short log if anyone thinks it could be a setting I may have inadvertently "adjusted."

Is the compressor running? If yes are the low side pipes or accumulator cold? That should tell you if it's a blend door.

I now don't think the compressor is running. I tried toggling it with the scanner, but that didn't seem to work either. I'll have to start doing some hardware diagnosing.

KOEO use the scanner to demand clutch on and off while someone checks to see if the compressor relay is clicking. If it is clicking use a test light at the compressor. If you have power and ground it is likely the clutch. If no power it is likely just a blown fuse or bad relay. Pick up a set of 9038a relay bypass switches. They are only $25. It will tell you if you have controlled circuit integrity. Otherwise you will need to go into the relay control wiring. Use the data when you demand clutch and see if your actual and commanded is good.

Or, you could just use the special functions in the VCM scanner, and command the compressor on, while the engine is running. If it engages, then the circuit is good. If its doesnt, then do what "TheMchanic" suggested, checking wiring and the compressor clutch.

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Originally Posted by PistolWhip

I now don't think the compressor is running. I tried toggling it with the scanner, but that didn't seem to work either. I'll have to start doing some hardware diagnosing.

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You could try looking at it.

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Originally Posted by 2xLS1

You could try looking at it.

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Uhhh, I did... That's why I said I don't think its running.

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Originally Posted by danmw2003

Or, you could just use the special functions in the VCM scanner, and command the compressor on, while the engine is running. If it engages, then the circuit is good. If its doesnt, then do what "TheMchanic" suggested, checking wiring and the compressor clutch.

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Maybe you didn't see my update. I said I did that and I now don't think the compressor is not running. thanks

Maybe use a definitive statement. Is the compressor running? Yes or no. That is different from "I don't think".