I need to take my crossfire in for service but havn't gotten around to it yet. One of the wierd things that's been going on is my fan control acts up randomly. I always leave it off when I get out of the car so usually what happens is I'll be driving for a bit and then decide to cut the air on and when I hit the very first notch from off it'll kick the fan on high. I usually turn it back to off and back to the first notch or alternate between off and the second notch and it goes back down to what I'd really selected.

If I leave it on the first notch sometimes it'll just vary between speeds and then settle on one. When it's really acting up I can turn it off and it'll continue to blow on high and then shut off completely after a minute or so and then for the rest of the ride you never know when its just going to turn itself on again.

I usually leave it completely off and roll down my windows so on the days I never use it at all it stays off without a problem. It's only once you fiddle with it that it gets possessed. Anyone had this problem?

Thanks!

 

Yes... Common problem. Ac fan doesn't know what speed... Or it would turn on and off when it was supposed to be off. Fixed it once a few years ago at the dealer under warranty. A few years later it broke again under warranty. Not sure if it wad the whole switch unit or a relay that broke.... Or both. Didn't really get into it because it was under warranty. I think it was an expensive fix.

 

Did you do a search?
There are all sorts of problems like this, take your pick.

 

I don't know what's going on with the switch but it sounds like it may be made of carbon contacts which can get worn from use and like carbon in a pencil they can actually spread accross the spectrum of the switch and cause a carbon trail to the next switch position, I've repaired a number of DVM's like this that acted up the same way. If you can get it apart it can be cleaned and that's probably all it needs. Alcohol and a Q-tip is a great cleaning team. Again, I don't know how it's made but it might be worth considering.

 

I replaced the blower resistor. Ordered from AutohausAZ for $106, order the one for a 2004 MB SLK 320-works great. That was over a year ago and haven't had any additional problems. Easy to change. Seach for "burnt smell coming from vents" thread from Jan 2010.

 

My cooling fan went haywire and ran without stopping after the car was off no matter the coolant temp -- I had to d/c the battery to kill it. Unless you are an electrical genius you won't be able to determine which part is failing. I had to replace the relay ($500+) after dealer diagnostics. Good luck.

 

Are you talking about the ENGINE fan? That would be the Fan Control Module - and I don't think I have ever heard of a verified failure of the FCM - not saying that it can't happen.