My 90 sdl will creep up to just over 100C in stop and go traffic. The aux. fans do not come on. If I jump the switch wires, the fans come on.

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82 300D....went to MB heaven
90 350 SDL....excercising con rods

I think mine only comes on when the AC is running.

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NC Benz
Fuquay-Varina, NC
1979 300D
1983 300D Turbo 260,000 Miles
1984 300D Turbo 345,000 Miles (sons car)
OBK #31
1998 Ford Expedition 5.4l (fer Haulin'!) 145,000
1973 19' SeaRay with 115 Mercury TOWER OF POWER!
Club Car Golf Cart 36V
Ex toys:
1967 Mustang 289 (First Car)
Fiat 124TC
1975 Honda CVCC
1980 Audi 5000 Turbo

I believe the W116 300SD was the only one to have the fan come on for a hot engine, except for the 190D 2.2 that had an electromagnetic fan clutch.

I believe the OM603 aux fan will come on without the AC on.
Here are the different switches

Red: 006-545-42-24 (100/110)
Green: 006-545-45-24 (105/115)
Grey: 006-545-61-24 (105/120)
Blue: 006-545-64-24 (105/128)

I have the red one in my car and the new one I put in failed at just over a year old. GSXR had one fail that was not very old as well. If you can jump it and it will come on, I would change the switch.

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1987 300TD 309, xxx 2.8.2014 10,000 mile OCI


Be careful of the toes you step on today, as they may be connected to the ass you have to kiss tomorrow. anonymous

“Be who you are and say what you feel, because those who mind don’t matter, and those who matter won’t mind.” Dr. Seuss

Thanks. I guess my motor doesn't get hot enough to trigger the on.
Is there a way to get a 90/100 switch?

__________________
82 300D....went to MB heaven
90 350 SDL....excercising con rods

You don't need a 90/100 switch. Your thermostat only fully opens at 90 I think. A 100/110 is fine and some think that is too low.

__________________
1987 300TD 309, xxx 2.8.2014 10,000 mile OCI


Be careful of the toes you step on today, as they may be connected to the ass you have to kiss tomorrow. anonymous

“Be who you are and say what you feel, because those who mind don’t matter, and those who matter won’t mind.” Dr. Seuss

With the Alum. head 100c would still be too hot for me.