I have a 2007 Altima. whenever I adjust the air flow from defrost to the floor, the AC turns on.

this is really annoying during the winter when I use the defrost the most. and with the heat on. so when I change it to blow the heat to the floor after my windows have defrosted the AC turns on and I have to hit the button to turn if off EVERYTIME.

I have talked to the dealership multiple times and they tell me this is normal. THIS IS NOT NORMAL. I had a 2006 Altima before this one and it did not have this problem.

Does anyone else have this issue?

my 01 civic did this... the way i fixed that one was via simple combination to reset (ie. push and hold certain buttons for a period of time). this helped for my civic, wonder if the altima would have the same "solution".

Do you have automatic or manual climate control?

I've had auto on both my 05 and my 07, and both of them like to run the A/C even in the winter. Doesn't seem to hurt anything and it cuts the humidity out of the air so the windows don't fog up so badly in the winter.

At least, that's my observation.

It is manual climate control.

so how does that work? running the AC during the winter. I understand how the AC will pull humidity out of the air but how does that effect the heat?

I have just always hit the button to turn the AC off when it cuts on when I switch the air flow from defrost to floor during the winter.

Actually this is quite normal. The thing is, most cars in the past turned on the A/C when you put the defroster on without giving you the option of turning it off. It's actually nice that the altima allows you to turn it off.

Air conditioning is a commonly thrown in with air cooling. Air conditioning is removing crap out of the air (your humidity, etc), and the cooling aspect usually gets thrown in with it. Having your A/C on during the winter will not affect anything but your gas mileage. The a/c is good at removing the dampness of the air so that your windows don't fog, but you can always turn it off if you don't want it on.

So again - it's normal for the a/c to come on when you hit anything with the defroster.

The air is just as warm (as far as I can tell) when it enters the cabin as it is w/o the A/C on. At any rate heating the car has never been an issue for me with the A/C still running. It's generally a good idea to leave it on when defrosting in particular as it pulls the moisture out which will prevent internal fogging on the windows (moist air + cold windows = condensation).

thanks guys. that explains it. I have always thought the AC would counter the heat.

macsteven wrote:thanks guys. that explains it. I have always thought the AC would counter the heat.

mines like that as well

This seems to be the latest thing. I had a 2000 Honda Accord that did the same thing. It was maddening. I begged the dealer for a change, but got no help. In the 2006 Accord there was no option to shut off the A/C, it just comes on without notification. So... now I own an Altima (08). At least I can shut off the A/C. I think it is a lame scheme from folks that live in damp (coastal) areas. I live in Denver, so it's worse than useless. The humidity here is already low and the compressor just eats gas. It makes me want to hunt down the automobile engineer that created it (there should be a bounty). Killing is too good.