JM124, the way you've stated your problem, leads me to wonder if you may be confusing your 2 auxiliary fans with the clutch fan (the single, main engine fan between radiator and engine block). Is that possible? Your aux fans (the 2 fans at the front of the car immediately behind the grille) do have two speeds. When you pull the connector off the blue sensor (key on, cool engine), that should give you hi speed on the 2 aux fans. Does that happen?

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1988 California version 260E (W124)
Anthracite Grey/Palomino
Owned since new and still going strong and smooth
MBCA member

Past Mercedes-Benz:
1986 190E Baby Benz
1967 230 Inherited from mom when she downsized
1959 220S Introduced me to the joys of keepin' 'em goin'

There are only 10 kinds of people in the world--those who understand binary and those who don't