It's getting cooler here in Arizona so I'm driving with either my windows down or sunroof open. I've noticed that the climate control sometimes just comes on by itself. I'll be driving and I'll notice that the a/c is on. I know I don't hit it accidentally or anything, it just comes on. I've told the dealer, but of course, they can't replicate it. Anyone else with this problem? Any fixes?

 

I think I read or heard something about the system comining on to remove moisture/humidity by itself. Not that there is a lot of humidity in Phoenix.

 

In "auto" setting AC, heat, etc will cycle depending on what sensors detect is required[ temp, humidity, etc]. You can defeat all climate by pushing the center round button "OFF" or touch the AC button so the light if off. That said, I suppose our smart cars also cycle the AC compressor to ensure the system circulates its fluids periodically for longevity. In the "old days" you were recommended to turn on the AC in the winter once in a while to do the same thing.

 

I've read the same thing in a few places on the forum. And, of course, my car does it too. I've even seen it come on in the winter.

As well as helping control humidity, it also helps the health of the ac system to run it periodically.

I don't worry about it anymore.

 

I'venever seen it, but then again I run my A/C all year long.

 

The A/C light may be on constantly, however that does not indicate the compressor is "on" constantly. It cycles on and off (determined by the controller's computer logic) on what climate conditions in and outside of the car.

Once again, in the "old days" when you turned A/C on it was ON.

That's why, when I hear "They don't make 'em like they used to!" I chuckle and say, "YUP, boy I really was psyched - every 12K miles - having to change spark plugs, points & condensers, cap and rotor ... mess with timing and carburetors ... YUP, those were the good old days!"

 

Wierd isn't it? I experienced the same thing. I also posted in the past about the same issue. Mine got as bad as I would turn it off only to have it turn itself back on within 30 seconds, sometimes almost immediately. I took it into BMW and of course it ceased to act this way. But they did a software upgrade, but it still happens. I've also heard the moisture/humidity thing but the days I took it off the humidity levels were real low. Take it to BMW and ask them to upgrade your software.

 

Luigi, do you know if the same is true with the E46 (the cycling on and off)?

 

My '86 524TD (E28) did .... so I suspect the same is true of later models. In the winter time the AC Compressor would cycle on and off on Defrost Cycle too as long as I had the "blue" AC button turned on. And I could tell it was cycling on and off even when the temp control was set at warm. If I recall, the manual said it was to dehumidify the inside air and reduce fogging.

 

It happens to me too. For a minute thought I was going crazy I've just gotten used to it now