M103 Aux Fan Questions

[John5788]

I have some questions about aux fan operation on a 1993 190E 2.6 with M103 motor.

1. What role does the aux fan resistor play?



I notice my aux fan resistor gets really hot and begins to smoke when I run the low fan speed test by shorting the pins to the AC drier pressure switch together. I think that alone calls for a replacement?

2. How much resistance should this aux fan resistor hold when I test it on the bench with a multimeter?

3. I read that the high speed fan test is to unplug the blue 2 pin connector on my cylinder head. I unplug this and the aux fans do not run. But if I put a 220ohm resistor on the wire plug, my aux fans run full speed. Is this correct?

4. Does both high speed and low speed fan current run through the aux fan resistor?