1989 240DL heater fan speed

fossil · Post by **fossil** » 28 Aug 2004, 18:40

The lowest speed setting of the heater control quit working, and I want to remove the switch and check it. However, I can't remove the knob to get the switch out of the dash. Is there a hidden tab somewhere? Are there multiple windings in the blower motor for the different speeds, or is the switch used to select different electrical resistances?

LaRy · Post by **LaRy** » 29 Aug 2004, 02:31

According to electrical drawings for your car, it is a separate resistor giving different speed steps, 1.9, 0.7 & 0.2 ohms. Most probably the low speed resistor is burned. I do not know exactly where it is placed in your car, but just follow the cables from the selector switch to the heater unit. Normally it is placed in the way that it is cooled by the airflow from the heater fan.