Fan stays on all the time...K1004V

[moynistan]

I am measuring for ground between blu/yel and 12V positive terminal

I get a reading of 11.85V between blue yellow with the realy IN (measuring where i tapped in for the switch)-that means its grounded right?

With the relay OUT, the voltmeter just wanders all over reading millivolts.  I have tested the relay and it functions correctly, but aren't these results telling me the relay is grounding the circuit?  Or is power going through the relay the back way, i.e. the short to ground you are taking about?

Thanks so much for your help.  I do ok with nuts and bolts, but this is killing me and probably you too, but I am so grateful to this site!

[Inge K.]

Since your relay and switch function as expected with the Motronic disconnected, the problem is on the Motronic side.

Never measured the Motronic signal to the relay, but I would expect it to be open or grounded (when temp is high enough), and not between as on yours (6,2 M ohm).

But you could also check both sensor wires that they ain`t shorted to ground.

Inge K.

[frankenduck]

Does your engine temp idiot light ever come on?