worked pretty good. A digital meter would help you read easier but sounds like your sensor is just fine.

So all's well that ends well!

__________________
Regards . . . . JimF
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'94 S500 Cpe

Visit my Mercedes Web Page

1995 S420,

I have installed a 1.1k resistor (same part number from Radio Shack) across CTS, as per JimF instructions. Problem: Aux fans do not come on even at 100C.

I measured R15 and R15a resistors (at idle since I could not get the fans to come on) and read 0.9 ohm and 0.6 ohm respectively, which are the same as JimF measures.

I measured for voltage and current at R15 & R15a and got nothing. I assume the relay is open.

I also measured the CTS pins at 500 ohm at 90 degrees C, which indicates a good CTS (I also do not get a trouble code). I confirmed the cool harness 1.1k resistor also measures 1.1k ohm.

The funny part is that when I set my Actron Digital Reader dialer at 200 Ohm and measure across the 1.1k resistor attached to CTS, the fans come on. They do not come on however when I set my Reader at 2000 ohm.

Any ideas to what is happening?

p.s. I have not measured the relay, since I am nnot sure how to. The relay box seems like a box with a bunch of relays inside, hermetically sealed.

When you say you are measureing ohms and the fans come on, it sounds like you are measuring resistance with the circuit energized; this is bad for the meter... pretty sure they use a voltage (the VOM's internal battery) to check resistance...

__________________
Bob Roe
Lehigh Valley PA USA
1973 Olds 88, 1972 MB 280SE, 1978 Datsun 280Z, 1971 Ford T-Bird, 1972 Olds 88, 1983 Nissan Sentra, 1985 Sentra, 1973 230.6, 1990 Acura Integra, 1991 Volvo 940GLE wagon, 1983 300SD, 1984 300SD, 1995 Subaru Legacy L wagon, 2002 Mountaineer, 1991 300TE wagon, 2008 Murano, 2007 R320CDI 4Matic 52K, some Hyundai, 2008 BMW 535xi wagon, all gone... currently
2007 Honda Odyssey Touring, 2014 E350 4matic