Quote:
Originally Posted by jbach36
Sometimes I start the car for the first time of the day, and the radiator fan comes on. Why does it do that, if the engine is at room temperature, 65 degrees?
Most times it does not turn on, but other times it does.
1991 300d, 207k
|
I had this same issue in my 95, it was solved after changing the push button unit for the AC/heater system in the dashboard - some loose solders cause this.
The high speed function of the fans are controlled by the unit as a trigger to a relay in the fuse box. The push button unit refers the coolant sensor on the front part of the head for this function. To test a normal system one just disconnects the sensor and the fans start on high.
The older cars 86-87 etc had a switch in place of the sensor directly controlling the high speed relay.