Based on everything I've read, the PWM signal comes from the ECU (pin 8) through a small purple wire to the fan module. I will backprobe the ECU with an o-scope to check if there is a square waveform. I discovered that my OBD2 scanner has a bi-directional control to activate the fan, so that makes testing a lot easier.

Best guess (before testing) is that the ECU is putting out a good PWM signal and I will need to trace the control wire to figure out why the signal isn't reaching the connector to the module. I've watched a couple Youtube videos where they found this thin signal wire was frayed/broken.