I have a 1989 300TE wagon. In cold weather, if the climate control is in the "normal" position and the fan control speed is set to "auto", it takes awhile for the fan/heat to come on. I was told this is normal and it takes awhile in the "auto" position because the coolant needs to warm up. If I set the fan control speed to either "high" or "low" the fan comes on immediately. Is my system working properly????

Yes, your mercedes is smart and keeps the coolant flow away via bypass from the heater core that would delay the engine warm up, when the engine warms up it "tells" the bypass valve it's ok now to flow warm water thru the heater core to heat the car, by pushing the high position on the fan you are just pushing cold air past the yet to be heated heater core.

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Jerry

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