What is the deal with my '05 G35's A/C light turning ON every time I start and warm up the car in this 10deg weather? I run my climate control on manual mode 90deg with forward vents (no defrost). On some of the other modes, I cannot turn off the A/C light. Also, the car defaults to circulation mode every time I start the car. I would like it to keep at the previous state, so I won't have to set it to my setting every time. Is this normal?

 

It's because it's on recirculate. The A/C always comes on in that mode to pull moisture from the air and prevent your windows from fogging up.

If you shut off the recirculate, does it let you shut the A/C off?

 

I think I got recirculate ("circulation") mixed up with fresh air. I meant that it defaults to fresh air mode.

Anyways, to answer your question, when I switch to fresh air mode, I am able to toggle the A/C. When in circulation mode, I cannot.

Also, when I switch to foot and window mode, I cannot switch to circulation or turn off A/C. I guess this is normal since A/C is used for de-fogging the car?

 

I'm pretty sure you can't shut off the A/C in our HVAC systems if you have it on any of the settings that include air blowing onto the windows (defog, foot/defog). Some vehicles will automatically turn the A/C when you switch to any defog mode but allow you to manually shut it off by pushing the A/C button, but I'm pretty sure our cars don't work that way. I know my Tacoma lets me and I usually do shut it off too.

 

Good news is, in the 2015 Q60 Coupe. You can recirculate the air without having the A/C on.

 

After reading the thread, I went and fired up my '06 to test a few things.

If I hit defrost, it will automatically turn on A/C, but it will let me turn it off. Same with putting it into any of the modes that include defrost. Auto on, but will let me turn it off.

Recirculate mode is A/C only though. If I turn the A/C off, it switches to pulling air from outside