A/C on-off switch

Mr. Detail · Post by **Mr. Detail** » 02 Mar 2020, 06:47

A question for you guys as I have dealt with this as long as I have owned this car. Since it is still the winter season here in the East (does not feel like) whenever I turn on the heat in the car, the "A/C" on-off switch automatically turns on without me touching it. I can even hear the compressor kick in under the hood.
I am constantly depressing this button to shut off the air conditioning. If I need a new switch, does anyone have a tip where to buy one other than the dealer? I am sure they will soak me for a new one. I am just assuming that it is the switch. Maybe you guys have another reason. Thanks!
(See attachment below)

Post by **Rattnalle** » 02 Mar 2020, 07:51

It's the normal behaviour. It's used for reducing the air moisture level in certain conditions apart from actually just cooling when it's hot. It shouldn't run a lot though.

And yes it's supposed to reset whenever you start the car.

With the caveat that I haven't actually seen one of these without ECC live.

Post by **vtl** » 02 Mar 2020, 08:09

Don't remember how it was in 02 with manual climate control, but in my 05 with automatic it stays off. Until window defrost is turned on.

Why it worries you? Air conditioner is used to dry the air, then it is heated in heating core. I turn it off, because the donor car I've got has no afterblow function enabled, that turns A/C evaporator into a stench generator. I'm planning on updating software and killing the mildew with enzymes later in spring.

Post by **abscate** » 02 Mar 2020, 12:27

It is sticky and should remember where you left it....unless you put the selector to DEFROST SSS in which case it always turns AC on.

Mr. Detail · Post by **Mr. Detail** » 03 Mar 2020, 13:55

Interesting, so you guys say this is normal behaviour for the switch. So when I want heat when the outside temperature is 25 degrees, it is normal for the A/C compressor to come on and stay on unless I manually hit the "OFF" side? Bizarre to me.

Post by **abscate** » 03 Mar 2020, 15:01

The compressor kicks over on start to make sure liquid gets dispersed. It won’t run if the air in the core falls below the set point, even if the green light is on.

My 2005 and 1999s all stay off if that’s where they are when the car is shut down