I'm not sure really when it happened but it seems that after I installed my new HU my AC Recirc Air and Rear Defrost Buttons do not work. I checked the relays and they are all fine. If its any help I used the metra harness for the HU. Oh and its a 07 Cobalt 2.2l LT. Thanks for any help or suggestions inda banging head against the wall

 

blew a fuse maybe?

 

Checked all fuses inside the car even the hvac relay all were good

 

hmm.. disconnect the HU and see what happens