Sensor A is for the engine temp guage

Sensor B is for the temp sensing of the glow plugs.

The "inside" fan, controlled by the clutch, is for normal engine cooling.

The "outside" fan comes on either when coolant temp. reaches 100*C or a pressure switch on the air conditioning system.

BTW, do you know of any independent foreign parts stores, that handle MB parts, in the Kansas City area? The last time I needed a part, while visiting my brother in Overland Park, all I heard was "only the dealer". Even his mechanic told me this.

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Sam

84 300SD 350K+ miles ( Blue Belle )