Manual A/C Blower Motor Speeds Incorrect
NOTE:
After making any repairs, perform BODY VERIFICATION TEST
under VERIFICATION TESTS.
Possible Causes:
- Control Head - Blower Speeds Incorrect
- Blower Motor Driver Circuit Open
- Blower Motor Resistor - Open Speed
Testing
- Disconnect the manual temperature control head C2 harness connector. See Figure . Turn ignition on. Measure the voltage between each of the blower motor driver circuits (cavities No. 2, 3, 7 and 10). If the voltage is 10 volts on each of the circuits, replace the control head. See appropriate MANUAL A/C-HEATER SYSTEMS article in HVAC. If the voltage is 10 volts or less on each of the circuits, go to next step.
- Turn ignition off. Turn the blower switch to the off position. Disconnect the blower motor resistor block harness connector. See Figure . Measure the resistance of each of the 4 blower motor driver circuits between the resistor block connector and the control head connector. If the resistance is 5 ohms or less on each of the circuits, replace the blower motor resistor block. See MANUAL A/C-HEATER SYSTEMS - CONCORDE & INTREPID article in HVAC. If the resistance is 5 ohms or more on each of the circuits, repair the blower motor driver circuit for an open.