HEELLP!!! Control Unit

[deykamp]

My car seems to be self destructing.
Replaced the alternator, I'm getting a knock sensor fault, and now a Control Unit Fault.

Running without the rear blower motor does not cause any issues, correct?
It doesn't actually assist in cooling the engine does it?
Does anyone rebuild/repair these units?

PROBLEM
It does not appear I'm getting any power to the rear main blower motor.
The ballast resistor, NTC, and the motor have been replaced ~ 2 years ago.

CHECKS
1) Their appears to be heat coming into the cabin (No blower motors, front or rear with temperature anywhere but fully counterclockwise, cold, blue dot.
2) The front blowers will come on when heat is on the blue dot.
3) The rear blower unit does not run on low or high.
4) Checked the ballast resistor, swapped relays, checked 30A fuse, don't think the sensor (NTC) would come into play.
5) the power defrost/demister switch turns on and shuts off.
6) I'm reading about 30 mV, could just be the multimeter, going to the rear blower.
7) Could it be anything but the control unit?

Any ideas/suggestions would be greatly appreciated.
I know the heater/AC unit is quite expensive...and cash is an issue....