Pinpoint Test M: The Auxiliary Blower Motor Does Not Operate Correctly
Climate Control System
Pinpoint Tests
Pinpoint Test M: The Auxiliary Blower Motor Does Not Operate Correctly
Refer to Wiring Diagram Set 52, Auxiliary Climate Control for schematic and connector information Diagrams By Number.
Refer to Wiring Diagram Set 54, Manual Climate Control System for schematic and connector information Diagrams By Number.
Normal Operation
Under normal operation, the auxiliary blower motor relay 1 coil receives a continuous ground. The relay 1 coil receives voltage from circuit CHA06 (YE/VT) if any position but OFF is selected. Voltage is supplied to the relay 1 switch from circuit SBB16 (VT/RD). When the relay 1 coil is energized, voltage is delivered to the blower motor through circuit CHA02 (BN/GN). Ground for the motor is provided through circuit CHA03 (GY/OG) from auxiliary blower motor relay 2. In any speed except HI, ground is provided to relay 2 switch through the auxiliary resistor. In HI, ground is provided to relay 2 switch through GD149 (BK/GY).
The auxiliary blower motor relay 2 coil receives voltage if any position but OFF is selected. When the auxiliary blower motor switch is in the HI position, ground is provided to the relay 2 coil. When relay 2 is energized, the auxiliary blower motor is grounded directly through a continuous ground.
The auxiliary blower motor is provided a ground from the resistor. The resistor gets a ground from the rear auxiliary blower switch. The rear auxiliary blower switch is provided ground through a continuous ground.
This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- Auxiliary blower motor switch
- Auxiliary blower motor resistor
- Auxiliary blower motor relay 1
- Auxiliary blower motor relay 2
PINPOINT TEST M: THE AUXILIARY BLOWER MOTOR DOES NOT OPERATE CORRECTLY
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M1 CHECK THE BLOWER MOTOR OPERATION
- Ignition ON.
- Select all auxiliary blower speed positions.
- Does the blower motor operate in any position?
Yes
If the blower motor does not operate in HI, GO to M2.
If the blower motor does not operate in MED, GO to M6.
If the blower motor does not operate in LO, GO to M7.
If the blower motor does not operate any speed except HI, GO to M8.
If the blower motor operates in HI at all times, GO to M9.
For all other symptoms, GO to M12.
No
GO to Pinpoint Test L. Pinpoint Test L: The Auxiliary Blower Motor Is Inoperative
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M2 CHECK CIRCUIT GD149 (BK/GY) FOR AN OPEN
- Ignition OFF.
- Measure the resistance between auxiliary high speed blower motor relay socket pin 5, circuit GD149 (BK/GY) and ground.
- Is the resistance less than 5 ohms?
Yes
GO to M3.
No
REPAIR circuit GD149 (BK/GY) for an open. TEST the system for normal operation.
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M3 CHECK CIRCUIT CHA08 (GN/OG) FOR GROUND
- Ignition OFF.
- Measure the resistance between auxiliary high speed blower motor relay socket pin 1, circuit CHA08 (GN/OG) and ground.
- Is the resistance less than 5 ohms?
Yes
CARRY OUT the relay test on the auxiliary blower relay. If the relay tests good, REPAIR circuit CHA08 (GN/OG) for an open. TEST the system for normal operation.
No
GO to M4.
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M4 CHECK CIRCUIT GD116 (BK/VT) FOR AN OPEN
- Ignition OFF.
- Measure the resistance between auxiliary blower motor switch C294C-6, circuit GD116 (BK/VT), harness side and ground.
- Is the resistance less than 5 ohms?
Yes
GO to M5.
No
REPAIR circuit GD116 (BK/VT) for an open. TEST the system for normal operation.
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M5 CHECK CIRCUIT CHA08 (GN/OG) FOR AN OPEN
- Ignition OFF.
- Measure the resistance between auxiliary high speed blower motor relay socket pin 1, circuit CHA08 (GN/OG) and function selector switch C294C-2, circuit CHA08 (GN/OG), harness side.
- Is the resistance less than 5 ohms?
Yes
INSTALL a new auxiliary blower switch. TEST the system for normal operation.
No
REPAIR circuit CHA08 (GN/OG) for an open. TEST the system for normal operation.
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M6 CHECK CIRCUIT CHA07 (BU/GY) FOR AN OPEN
- Ignition OFF.
- Measure the resistance between auxiliary blower motor resistor C4107-2, circuit CHA07 (BU/GY), harness side and auxiliary blower switch C294C-5, circuit CHA07 (BU/GY), harness side.
- Is the resistance less than 5 ohms?
Yes
CARRY OUT the component test on the auxiliary blower motor resistor. If the resistor tests good, INSTALL a new auxiliary blower switch. TEST the system for normal operation. Auxiliary Blower Motor Resistor
No
REPAIR circuit CHA07 (BU/GY) for an open. TEST the system for normal operation.
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M7 CHECK CIRCUIT CHA06 (YE/VT) FOR AN OPEN
- Ignition OFF.
- Measure the resistance between auxiliary blower motor resistor C4107-4, circuit CHA06 (YE/VT), harness side and auxiliary blower switch C294C-3, circuit CHA06 (YE/VT), harness side.
- Is the resistance less than 5 ohms?
Yes
CARRY OUT the component test on the auxiliary blower motor resistor. If the resistor tests good, INSTALL a new auxiliary blower switch. TEST the system for normal operation. Auxiliary Blower Motor Resistor
No
REPAIR circuit CHA06 (YE/VT) for an open. TEST the system for normal operation.
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M8 CHECK CIRCUIT CHA04 (GN/WH) FOR AN OPEN
- Ignition OFF.
- Measure the resistance between auxiliary high speed blower motor resistor C4107-1, circuit CHA04 (GN/WH), harness side and auxiliary high speed blower relay pin 4, circuit CHA04 (GN/WH).
- Is the resistance less than 5 ohms?
Yes
CARRY OUT the component test on the auxiliary blower motor resistor. If the resistor tests good, INSTALL a new auxiliary blower switch. TEST the system for normal operation. Auxiliary Blower Motor Resistor
No
REPAIR circuit CHA04 (GN/WH) for an open. TEST the system for normal operation.
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M9 CHECK CIRCUIT CHA08 (GN/OG) FOR A SHORT TO GROUND
- Ignition OFF.
- Measure the resistance between auxiliary high speed blower motor relay socket pin 1, circuit CHA08 (GN/OG) and ground.
- Is the resistance greater than 10,000 ohms?
Yes
GO to M10.
No
REPAIR circuit CHA08 (GN/OG) for a short to ground. TEST the system for normal operation.
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M10 CHECK CIRCUIT CHA03 (GY/OG) FOR A SHORT TO GROUND
- Ignition OFF.
- Measure the resistance between auxiliary blower motor C4106-2, circuit CHA03 (GY/OG), harness side and ground.
- Is the resistance greater than 10,000 ohms?
Yes
GO to M11.
No
REPAIR circuit CHA03 (GY/OG) for a short to ground. TEST the system for normal operation.
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M11 CHECK CIRCUIT CHA04 (GN/WH) FOR A SHORT TO GROUND
- Ignition OFF.
- Measure the resistance between auxiliary high speed blower motor relay pin 4, circuit CHA04 (GN/WH) and ground.
- Is the resistance greater than 10,000 ohms?
Yes
INSTALL a new auxiliary high speed blower motor relay. TEST the system for normal operation.
No
REPAIR circuit CHA04 (GN/WH) for a short to ground. TEST the system for normal operation.
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M12 CHECK CIRCUIT CHA04 (GN/WH), CHA07 (BU/GY) AND CHA06 (YE/VT) FOR A SHORT TO GROUND
- Ignition OFF.
- Measure the resistance between ground and auxiliary blower motor resistor:
- C4107-1, circuit CHA04 (GN/WH), harness side.
- C4107-2, circuit CHA07 (BU/GY), harness side.
- C4107-4, circuit CHA06 (YE/VT), harness side.
- Are the resistances greater than 10,000 ohms?
Yes
GO to M13.
No
REPAIR the affected circuit(s) for a short to ground. TEST the system for normal operation.
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M13 CHECK CIRCUITS CHA07 (BU/GY), CHA06 (YE/VT) AND CHA04 (GN/WH) FOR A SHORT TOGETHER
- Ignition OFF.
- Measure the resistance between blower motor resistor:
- C4107-4, circuit CHA06 (YE/VT), harness side and C4107-2, circuit CHA07 (BU/GY), harness side.
- C4107-2, circuit CHA07 (BU/GY), harness side and C4107-1, circuit CHA04 (GN/WH), harness side.
- C4107-4, circuit CHA06 (YE/VT), harness side and C4107-1, circuit CHA04 (GN/WH), harness side.
- Are the resistances greater than 10,000 ohms?
Yes
GO to M14.
No
REPAIR the affected circuit(s) for a short together. TEST the system for normal operation.
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M14 CHECK CIRCUIT CHA02 (BN/GN) FOR A SHORT TO VOLTAGE
- Ignition OFF.
- Measure the voltage between auxiliary high speed blower motor C4103-2, circuit CHA02 (BN/GN), harness side and ground.
- Is any voltage present?
Yes
REPAIR circuit CHA02 (BN/GN) for a short to voltage. TEST the system for normal operation.
No
CARRY OUT the component test on the auxiliary blower motor resistor. If the resistor tests good, INSTALL a new auxiliary blower switch. TEST the system for normal operation. Auxiliary Blower Motor Resistor
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