Can anyone tell me where the auxillary fan relay is located on a 1979 300SD? Applying a jumper to the fan from the battery makes it come on, but shorting the leads from the high temp switch on the AC dryer does not. The auxillary relay seems to me to be the next logical step.
Dave
The fan on my '80 300SD runs when I ground the wire to the temperature sensor on the thermostat. Suggest first you try that jump before the relay.
I suggest you change all the temperature sensor switch on your engine... they are old.
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