while we are discussing aux fans
I took the '95 300D to the drag races this weekend and noticed that when I got into traffic the aux fans did not come on. I got out and "spun one of the fans by hand and then they both came on like they should. The next day I got the car up to operating temp, turned the a/c on and the fans did not come on. I got out again and "spun" by hand (by turing the round housing in the middle to keep it safe). Again both fans came on. Sounds like I need to start checking/cleaning the connections. My question is which system provides "grounding" for this circuit.