I tested the temperature sensor and it indicates a closed switch with the engine cold. I figured disconnecting the wire would simulate an open switch, but the fan still runs at full speed. So, I do need a new temperature switch because it is closed when it should be open.

The AC switch is open as it should be.

I can not find the resistor. It is not anywhere near the headlight or the inner fender. I even disassembled the fuse box to see if it was in there. Not there.

1) By disconnecting the temperature switch, wouldn't that be the same as having a NO switch? It is only a one wire switch.
2) Anybody know where this resistor is? What should its resistance be?
3) What else can cause my issue?

Thanks
Fred

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Thank You!
Fred
2009 ML350
2004 SL600
2004 SL500
1996 SL600
2002 SLK32
2005 CLK320 cabrio
2003 ML350
1997 C280 Sport