Mercedes s430 radiator fan stopped working. Replaced the fan motor and controller with a used unit from eBay. Still doesn't work. Has 12 volts and ground at the connector. Has 12 volts at the small wire to the controller has a weak signal from the ecm at .38 volts and 7hz. The signal is the same weather the ac is on or off. The gauge works so the temp. Sensor is working. I have no communication with the Ecm so if a code has been set I can' clear it. All fuses are good. Check engine light is on.