Electro Magnetic Fan Not engaging with new switch
 

For many years and since I have owned my car (w123 230CE) it has had an electric fan instead of the correct electro magnetic fan connected to the water pump . I assumed at some point the fan switch had failed and somebody thought it was easier to put on an electric fan then find the right parts.

Fast forward today, I now have all the original parts (fan, bolts, shroud, etc) and I wanted to restore it to factory spec.

I cannot get the fan to work. I have purchased a new Behr switch that was the same part as removed and the behavior is the same. It will not turn on with brand new switch.

Thinking it may be something in the wiring, I grounded out the connecting plug and the fan engages as it should.

I have also cleaned out the connecting plug and ensured I have a solid connection to the switch. I also tested with a third previously thought to be good switch and it yielded the same results.

Any ideas what my issue might be? Did I get a bad switch from Behr?

Thanks

What's the temp trip point of the switch and is the engine getting hot enough? Aim an IR thermometer at the base of the switch.

Sixto
83 300SD
98 E320 wagon

Switch is 100c on 95c off.

My temp on my gauge pushed slightly above 100-105c, then I shut it down.

I was putting my IR themo on the thermostat housing and getting a similar reading.

I suppose gauge could be reading higher than it is getting on the switch. I'll double check that.


Sent from my iPhone using Tapatalk

Dunno how much of a pain it is to take the switch out again, but in this situation I'd test it with a multimeter and a heat source such as a soldering iron. Sounds like you have other issues though, since you've tried it with another switch.

Does the fan come on if you jumper the lead to the switch? That's how I'd test the rest of the circuit...