Allikatzpop

My aux fans run any time the ignition is on. This started after replacing AC
dryer and the green pressure switch ( w/ aftermarket) as soon as the switch is unplugged fans stop. My question is: could this be the wrong switch? Does anyone have a good MB # for the original The # I have (002-820-52-10) is a dead end..
Thanks...

Plutoe

There has been a number of changes---the current part number is 004 820 68 10 and I wouldent FA with a non MB part.

topianno

I have the same problem lately. I haven't changed anything. All of a sudden whenever I fire the car up the fan kicks on...

SteveE400

I'm not familiar with your model car, but many of these fan switches are designed so that their "default" failure mode turns the fan on all the time. This way, if the switch fails, at least the engine won't overheat and suffer damage.


It could also be the wrong switch.