I'm not sure how the controller works. Andrewh was playing with lower voltage to the trigger on his fan and it seemed to run slower.
I have not tried that on the hot rod.

PWM may or may not work on this setup. There's something different about this fan. Putting direct current on the windings resulted in a fan that shuddered back and forth. It would not spin in complete revolutions.

The new style and old style fans are interchangeable on the Mercedes. They operate with the same input but the newer version runs at 90% with a constant 12 volts to teh trigger.

We are brothers and sisters doing time on the planet for better or worse. I'll take the better, if you don't mind.
- Stu Harmon