Troubleshooting AC issues on 2004 z71

My AC was dead so finally had a mechanic fix it. Evidently the compressor would not turn on so they replaced compressor, condenser, and related parts.

Since it has been fixed, the front is not working properly. When you turned on AC, it used to blow fan full force until correct temp was achieved. Then the fan would kick down and it was perfect temp. Now the fan does not kick down and it just does not feel as comfortable. I have to adjust it manually (pushing the fan button down). Any ideas? could this be a bad module?

The rear blend door is not operating (blowing hot) and so they temporary disconnected it so that it was stuck on cold for summer. I had replaced the rear module about 8-9 years ago, so it seems weird that it would be dead already.

Is there a way of troubleshooting modules with a computer?

Auto mode (if an option) would be the only way it would adjust fan speed on its own to my knowledge. The blend door for the rear likely has a bad actuator, or the door is binding and sticking causing it to get stuck

TXt3rr0r said:

Auto mode (if an option) would be the only way it would adjust fan speed on its own to my knowledge.

Click to expand...

^^^ This. Only in AUTO will it change the fan speed automatically.

A Tech 2 would help you command the various modes and speeds, and would also show if the temp sensors in the ducts are reading correctly for AUTO to work properly.

There is an aspirator in the headliner above the driver's left ear; those can get clogged with dust and you can try to blow it out with canned air or low compressor psi. It's replaceable.