This is my second FCM - brand new.
The first one worked for a short period and now this new one doesn't work at all.

I was sure to ground the correct side of the cut wire (going into the harness not back to the ECU). It does nothing at all.
Yet if I just jump on the harness, the ground to ground to fan and power to power to fan it turns the fan on very high.

When I check at the harness, the small red/***** wire is power all the time and the gray wire seems to be ground. I am still unsure why I have a small red/white wire in addition to the gray one that goes into the FCM. I agree that I should get the FCM working correctly first and only then go back to the ECU. However, I bought two brand new FCMs and still doesn't work.
Seems like I have such a strange issue and not the normal type problem on this thing.