would anyone have a reference to the resistive value for the b10/8 coolant temperature sensor loacted at the front of the engine(color is green) on a 1991 350sdl? this one has the dual aux fans and they both run with a/c on but will not come on at 105c. unless i unplug the connector attached to the green sensor the fans never energize. this sensor has about 550 ohms when i think it should be on and cooling the engine,but can find any reference to a nominal resistance value in my cd manual.
did research the forum.
larry perkins
72 old cars

ok forum i will ask this another way as i am still lost.
the 603.96 and the 603 97 engine cooling ckt seems to be the same so could some one pull the connector from the green sensor at the front of the engine and tell me is the aux fan(or fans) start running? of course this assumes a <105c temp and aux not running when preformed.
thanks
larry perkins
72 old cars

If you pull the connector and the fans run, your fans and the power supply to them are all ok. The thermal switch is dead. Jim

__________________
Own:
1986 Euro 190E 2.3-16 (291,000 miles),
1998 E300D TurboDiesel, 231,000 miles -purchased with 45,000,
1988 300E 5-speed 252,000 miles,
1983 240D 4-speed, purchased w/136,000, now with 222,000 miles.
2009 ML320CDI Bluetec, 89,000 miles

Owned:
1971 220D (250,000 miles plus, sold to father-in-law),
1975 240D (245,000 miles - died of body rot),
1991 350SD (176,560 miles, weakest Benz I have owned),
1999 C230 Sport (45,400 miles),
1982 240D (321,000 miles, put to sleep)