Rear Booster Fan Runs At Only One Speed - ATC

Test 1 - 2:

Test 3:

SYMPTOM
REAR BOOSTER FAN RUNS AT ONLY ONE SPEED - ATC

POSSIBLE CAUSES
- Automatic temperature control (ATC) DTC(s) present
- Rear booster fan control circuit shorted to ground
- Automatic temperature control (ATC)
- rear booster fan power module