I read that thread and lots of the others. I don't want to bother you guys without doing my homework. My main question is that my temp sensor (ECT) is apparently part of a 4 wire sensor instead of the typical single wire resistor to ground or 2 wire variable resistor with an in and an out. If the resistance is around 300 ohms to turn on the fans, I can jump with a small 200 or 300 ohm resistor to eliminate the sensor but I don't want to jump the wrong thing. I bought the CD for the 202 from MBZ USA but it does not feature much of the 104 engine - mostly the 111, 112, and 113, and the wiring diagrams, split up and poorly titled, are a nightmare to follow. I did find the B11/4 temp sensor and saw a picture of it, but the wiring diagram shows just 2 wires so the other half must be for something else. Oddly enough, if I unplug the pressure sensor off the expansion bottle for the air cond, the high speed fan comes on and stays on until the temp gauge get down to about 90 - that shows that the high speed relay, fuses, wiring, resistors, and fan motors are working. I am suspecting the sensor since occasionally the high speed fans come on if I run the air cond at idle long enough for the engine to heat up, but it takes a long time. Even then, the fans at high speed stay on only about 5 seconds.