Test Q: The Auxiliary Blower Motor Does Not Operate Correctly
PINPOINT TEST Q: THE AUXILIARY BLOWER MOTOR DOES NOT OPERATE CORRECTLYNormal Operation
Under normal operation, ground for the blower motor is provided through circuit CHA03 (GY/OG) from the blower motor resistor. The blower resistor is grounded through circuit GD147 (BK/VT). The blower motor speed relay coils are supplied through circuit CBP45 (YE). Blower motor speed is received by the electronic automatic temperature control (EATC) module from the rear auxiliary control through circuit VHA17 (VT/GN). Reference voltage for the blower speed selector resistor is provided by the EATC module through circuit LH111 (BN/WH). When the relay 1 coil is energized, voltage is delivered to the blower motor through circuit CHA02 (BN/GN). The auxiliary blower motor relay coil receives ground from the EATC module through circuit CH112 (VT/WH) if any blower speed but OFF is selected.
In LO, ground for the blower motor is provided through the blower motor resistor.
In MED-LO, blower motor speed relay 3 is grounded by the EATC module through circuit CH114 (GN/WH). Blower motor ground circuit CHA03 (GY/OG) is connected through one half of the blower motor resistor to circuit CHA04 (GN/WH). Circuit CHA04 (GN/WH) is connected through blower motor speed relay 3 to the blower motor resistor through circuit ZA110 (OG/YE). The blower resistor is grounded through circuit GD147 (BK/VT).
In MED-HI, blower motor relay 2 is grounded by the EATC module through circuit CH113 (VT/GY). Blower motor ground circuit CHA03 (GY/OG) is connected through blower motor speed relay 2 to circuit CHA04 (GN/WH). Circuit CHA04 (GN/WH) is connected through one half of the blower motor resistor to the blower motor resistor to ground circuit GD147 (BK/VT).
In HI, blower motor speed relays 2 and 3 are grounded by the EATC module through circuit CH114 (GN/WH) and CH113 (VT/GY). Blower motor ground circuit CHA03 (GY/OG) is connected through blower motor speed relay 2 to circuit CHA04 (GN/WH). Circuit CHA04 (GN/WH) is connected through blower motor speed relay 3 to the blower motor resistor ground circuit GD147 (BK/VT) by circuit ZA110 (OG/YE).
This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- Auxiliary blower motor relay
- Auxiliary blower motor speed relay 1
- Auxiliary blower motor speed relay 2
- Auxiliary blower motor speed relay 3
- Auxiliary blower motor resistor
- EATC module
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