M42 coolant level sensor missing

[18rabbit]

Ok, I feel like this is going to be a real simple and shameful solution but by God I have no clue where this thing is and I've spent hours searching for an answer, and I'm a seasoned auto-issue searcher!

I have a '91 318is M50 with a M42 radiator. The OBC coolant light is on. There is no coolant level sensor or wiring anywhere. I compared on realoem.com and where the sensor 'goes' there is just a rubber plug on the rad. There is one wire which has a blue two prong female plug, is this the coolant level harness? I tried jumping these wires but it does not turn out the light.

I would like to have a functioning coolant level sensor. Please guide me e30bros.

[AndrewBird]

It is screwed into the bottom of the plastic expansion tank on the side of the radiator. It is a float switch.

[18rabbit]

It is screwed into the bottom of the plastic expansion tank on the side of the radiator. It is a float switch.

Oh ok, so like the E36's. My radiator definitely doesn't have that sensor installed. Anyone have a p/n for this switch? realoem.com has it pictured but no p/n. Nor does any online parts place have that switch listed...