Electro Magnetic Fan Not engaging with new switch

[BlackDog_4596]

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