1984 SD Heater Fan Motor Speed Control - Mercedes-Benz Forum

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post #1 of 2 (permalink) Old 02-13-2011, 09:53 PM Thread Starter
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Date registered: Feb 2011
Vehicle: 1984 300SD Silver
Location: Santa Rosa CA.
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1984 SD Heater Fan Motor Speed Control

My 1984 300 SD 228K miles,

My Fan motor speed will run normally with plenty of power and air moving well, then slow down to almost nothing. All by itself. I can even hear a slight blade dragging sound as it slows to almost nothing. It's as if something is warming up or getting too hot then it drops rpm within 10 seconds. It has gotten worse and worse. This is during manual all on and not while on "auto"

At the same time I am experiencing a coolant leakage from the remote reservoir but just a slight dripping from the middle of the tank and not the hoses!
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post #2 of 2 (permalink) Old 02-14-2011, 10:08 AM
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Check the blower motor regulator, problem with those have been reported on other forums. You might also check your native forum for answers (W126 I think).

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