Pinpoint Test K: The Blower Motor Does Not Operate Correctly
Climate Control System
Pinpoint Tests
Pinpoint Test K: The Blower Motor Does Not Operate Correctly
Refer to Wiring Diagram Set 54, Manual Climate Control System for schematic and connector information. Diagrams By Number
Normal Operation
Under normal operation, the blower motor is provided a ground from the blower resistor through circuit CH430 (VT/OG). The resistor gets a ground from circuit GD123 (BK/GY) in the lowest blower setting. In MED-LO and MED-HI the resistor gets a ground through circuit CH428 (GN/WH) or CH429 (GY/BN), depending on selected speed. In HI, the blower motor is grounded directly through the blower switch from circuit CH430 (VT/OG) to circuit GD116 (BK/VT). The blower switch receives its ground from circuit GD116 (BK/VT).
This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- Blower motor resistor
- Blower motor switch
PINPOINT TEST K: THE BLOWER MOTOR DOES NOT OPERATE CORRECTLY
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K1 CHECK THE BLOWER MOTOR OPERATION
- Ignition ON.
- Turn the function selector switch to the FLOOR position.
- Select all blower speed positions.
- Does the blower motor operate in any position?
Yes
If the blower motor does not operate in HI, GO to K2.
If the blower motor does not operate in MED-HI, GO to K3.
If the blower motor does not operate in MED-LO, GO to K4.
If the blower motor does not operate in LO, GO to K5.
For all other symptoms, GO to K9.
No
Go To Pinpoint Test J. Pinpoint Test J: The Blower Motor Is Inoperative
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K2 CHECK CIRCUIT CH430 (VT/OG) FOR AN OPEN
- Ignition OFF.
- Disconnect: Blower Motor Switch C294b.
- Disconnect: Blower Motor C1227.
- Measure the resistance between blower motor switch C294b-2, circuit CH430 (VT/OG), harness side and blower motor C1227-2, circuit CH430 (VT/OG), harness side.
- Is the resistance less than 5 ohms?
Yes
GO to K7.
No
REPAIR circuit CH430 (VT/OG) for an open. TEST the system for normal operation.
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K3 CHECK CIRCUIT CH429 (GY/BN) FOR AN OPEN
- Ignition OFF.
- Disconnect: Blower Motor Switch C294b.
- Disconnect: Blower Motor Resistor C1228.
- Measure the resistance between blower motor switch C294b-3, circuit CH429 (GY/BN), harness side and blower motor resistor C1228-2, circuit CH429 (GY/BN), harness side.
- Is the resistance less than 5 ohms?
Yes
GO to K4.
No
REPAIR circuit CH429 (GY/BN) for an open. TEST the system for normal operation.
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K4 CHECK CIRCUIT CH428 (GN/WH) FOR AN OPEN
- Ignition OFF.
- Disconnect: Blower Motor Switch C294b.
- Disconnect: Blower Motor Resistor C1228.
- Measure the resistance between blower motor switch C294b-4, circuit CH428 (GN/WH), harness side and blower motor resistor C1228-4, circuit CH428 (GN/WH), harness side.
- Is the resistance less than 5 ohms?
Yes
GO to K5.
No
REPAIR circuit CH428 (GN/WH) for an open. TEST the system for normal operation.
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K5 CHECK BLOWER MOTOR RESISTOR GROUND
- Measure the resistance between blower motor resistor C1228-3, circuit GD123 (BK/GY), harness side and ground.
- Is the resistance less than 5 ohms?
Yes
GO to K6.
No
REPAIR circuit GD123 (BK/GY) for an open. TEST the system for normal operation.
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K6 CHECK CIRCUIT CH430 (VT/OG) FOR AN OPEN
- Connect: Blower Motor C1227.
- Measure the resistance between blower motor resistor C1228-1, circuit CH430 (VT/OG), harness side and blower motor C1227-2, circuit CH430 (VT/OG), harness side.
- Is the resistance less than 5 ohms?
Yes
GO to K7.
No
REPAIR circuit CH430 (VT/OG). TEST the system for normal operation.
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K7 CHECK THE BLOWER MOTOR SWITCH CIRCUIT GD116 (BK/VT)
- Measure the resistance between blower motor switch C294b-1, circuit GD116 (BK/VT), harness side and ground.
- Is the resistance less than 5 ohms?
Yes
GO to K8.
No
REPAIR circuit GD116 (BK/VT). TEST the system for normal operation.
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K8 CHECK THE BLOWER MOTOR RESISTOR
- Carry out the blower motor resistor component test. Blower Motor Resistor
- Does the blower motor resistor test good?
Yes
INSTALL a new blower motor switch. TEST the system for normal operation.
No
INSTALL a new blower motor resistor. TEST the system for normal operation.
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K9 CHECK CIRCUITS CH430 (VT/OG), CH429 (GY/BN) AND CH428 (GN/WH) FOR A SHORT TO GROUND
- Ignition OFF.
- Disconnect: Blower Motor C1227.
- Disconnect: Blower Motor Resistor C1228.
- Place the blower switch in the lowest setting.
- Measure the resistance between ground and blower motor resistor:
- C1228-1, circuit CH430 (VT/OG), harness side.
- C1228-2, circuit CH429 (GY/BN), harness side.
- C1228-4, circuit CH428 (GN/WH), harness side.
- Are the resistances less than 5 ohms?
Yes
GO to K10.
No
REPAIR the affected circuit for a short to ground. TEST the system for normal operation.
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K10 CHECK THE BLOWER MOTOR CIRCUITS FOR SHORTS TOGETHER
- Measure the resistance between blower motor resistor:
- C1228-4, circuit CH428 (GN/WH), harness side and C1228-1, circuit CH430 (VT/OG), harness side.
- C1228-4, circuit CH428 (GN/WH), harness side and C1228-2, circuit CH429 (GY/BN), harness side.
- C1228-1, circuit CH430 (VT/OG), harness side and C1228-2, circuit CH429 (GY/BN), harness side.
- Are the resistances greater than 10,000 ohms?
Yes
INSTALL a new blower motor switch. TEST the system for normal operation.
No
REPAIR the affected circuits for a short together. TEST the system for normal operation.
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