Hello guys, I've been dealing with this problem for 2 years now. I replaced the ambient temp sensor and through the diagnostics menu it still reads -22 and still no a.c. I've been using the a.c through the diagnostic menu the past 2 summers but it's getting frustrating, I also replaced my a.c amplifier yesterday and although that fixed my faulty fuel guage issue it didn't fix the a.c issue. Of course I checked the a.c fuse on the driver side and still didn't fix it. I checked for corrosion on the ambient temp sensor wires and didn't find anything out of the ordinary. If anyone has went through this specific problem and found a fix, it will be greatly appreciated if you can tell me how you fixed it. My car is a 2008 g35x. I will note that the same day a friend hooked up my subs is the same day that this problem occurred, however he did not mess with any a.c fuses or even the temp sensor so I considered it a weird coincidence. A.c still blows icy cold when used through the diagnostics menu, I just can't control the speed of the blower or the vents when doing it like that, which sucks when it's been parked in the sun.

 

Sounds like something was either damaged or unplugged behind the head unit when he was doing the amplifier.

Just out of curiosity did he pull new power wires for the amp?

Does this problem go away when you unplug the amp?