Hello everyone,
I hope someone can guide me see if the module is bad or not. I have a 2001 A6 Avant Quattro with 197000 miles on it that up and died on me on my way home some time ago. After I got it towed home, and after searches, diagnostics, and testing I finally got it running, turned out to be the fuel pump had gone bad. My dilemma now is that it now has a heating problem. After further testing I came to conclusion that my thermostat is stuck. This was proven by pulling the inlet hose to the core and not seeing any coolant come out. I then pulled the hose completely off and the flow was very minimal. I ordered the thermostat and water pump and going to do it this weekend I am also replacing the upper and lower hoses as they felt very soft to me.
Now my question concerns the fan control module. Through my diagnosing the heating problem I had noticed that neither of the electric fans were turning on. I already replaced the fan control switch on the lower hose so I went to test the fan control module. I read that to test this you need to jump pins 1 and 2 on the fan connector and turn the key to "on" without stating. The fans did not turn on. I did the same jumping pins 3 and 4 with the same result. Now, I started the car and then proceeded to jump the pins again. This time pins 1 and 2 turned on the fan in low and pins 3 and 4 to high. Does this mean I still need to change the module? Since the thermostat is suspected stuck, my thinking is that the fan sensor on the lower hose never reaches the correct temp to get the fans going. Can someone advise please. Thanks in advance.