hockeyfan77

This may be an incredibly dumb question, but I admit to not being too car savy. Why does my AC light engage when I turn on the defrost?

Faja

I think that light might also signify that the air is being recycled. I did notice that on my Sentra and asked myself the same question, I think it's in the manual somewhere but of course I haven't read it line by line!!!

snoopdogie187

I think it actually uses the a/c for the front window defrost. The cold air usually works better and I helps as a dehumdifier.

So good part is it does work better usually, bad part is I don't know if you can turn it off, and it will decrease power/gas millage.

I think it would also be better in the winter time, less chance of causing too much of a temp change in the glass and cracking it (not that I ever saw that happen before) but yet its still is warmer than freezing

monoshock

One advantage of the a/c coming on with the defrost is the a/c compressor will be engaged in the colder months so the compressor isn't setting in idle all winter.