99 e320 aux fan
 

the car drives about 30 miles in warm weather. instument cluster gives a warning for aux fan problem. turn off a/c and warning goes away

To test the fan:

With the key in position 2, press and hold both AUTO buttons on the climate control pushbutton control module for >10 seconds. It takes about 12 seconds for my car. The fan should start running at full speed.

Matt, I followed your steps on a trouble shooting of my aux. fans (99 e320 aux fan thread). They were put on about a year ago and I have never heard them run after replaced. I did get them going with your advice but only after a little rotation from my part. Any advice