Temperature Switches
 

Hello!


I'm having an issue with my w201 2.5 and I can't find a straight answer anywhere.


So I've read diagrams, traced electrical wires, etc. but a question remains. What switch triggers the fan clutch when the temperatures rises? Mine is always rotating (I think it's normal), but I've never been past 80ºC, so I really don't know if the switch is working, or if someone decided to short it to make the fan work permanently.


I have 2 temperature sensors, one in the thermostat housing (to show in the gauge), and other in the engine block, for the ignition. Is some of these sensors used for the fan? And how to test if the fan clutch is working?


Thanks! :)

Somewhere in the manual there is a testing protocol, which I follow every spring: block the radiator with cardboard and run the engine at high idle until the engine temps get above 100d: in my case the fan doesn’t engage until nearly 110 or more. It takes a while, but is dead easy. The difference in the speed of the fan blades is obvious, as well as the noise it makes. I have the electromagnetic clutch not the viscous.

Hello, thanks for the reply!


How do you differentiate from each type? One should have a electrical harness right? Mine doesn't.

Doesn't the om602 have a viscous clutch fan?

I think is does, it's on the engine and from pictures around it seems so.

So there is no switch. I know the m102 and om601 had a mechanical fan with an electric clutch.