1999 323i Aux Fan Issue - Technical answers needed

[ninety1two40]

@GearheadNY.com

Right on, good observation. I foud out in a few different steps. I checked the wire for continuity/resistance and then checked the operation of the fan control pulse at the pin directly on the DME. What I got was a whole lot of nothing exceptfor a very small amount of voltage, which could be back feeding through the circuit. That’s what I Think is happening.

If you are trying to measure a PWM signal it will only be a 1-3V on a regular multimeter.