Pinpoint Test P: The Blower Motor Does Not Operate Correctly - Manual Climate Control
Climate Control System
Pinpoint Test P: The Blower Motor Does Not Operate Correctly - Manual Climate Control
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 261 (OG/BK). The blower motor resistor gets a ground from circuit 57 (BK) in the lowest blower setting. In MED-LO and MED-HI the resistor gets a ground through circuit 752 (YE/RD) or 754 (LG/WH), depending on selected speed. In HI, the blower motor is grounded directly through the blower motor switch from circuit 261 (OG/BK). The blower switch receives its ground from circuit 57 (BK).
This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- Blower motor switch
- Blower motor resistor
PINPOINT TEST P: THE BLOWER MOTOR DOES NOT OPERATE CORRECTLY - MANUAL CLIMATE CONTROL
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P1 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 P2.
If the blower motor does not operate in MED-HI or MED-LO, GO to P4.
If the blower motor does not operate in LO, GO to P5.
All other symptoms, GO to P8.
No
Go To Pinpoint Test O. Pinpoint Test O: The Blower Motor Is Inoperative - Manual Climate Control
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P2 CHECK CIRCUIT 57 (BK) FOR AN OPEN
- Ignition OFF.
- Disconnect: Blower Motor Switch C294b.
- Measure the resistance between blower motor switch C294b-2, circuit 57 (BK), harness side and ground.
- Is the resistance less than 5 ohms?
Yes
GO to P3.
No
REPAIR circuit 57 (BK) for an open. TEST the system for normal operation.
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P3 CHECK CIRCUIT 261 (OG/BK) FOR AN OPEN
- Disconnect: Blower Motor C1227.
- Measure the resistance between blower motor switch C294b-3, circuit 261 (OG/BK), harness side and blower motor C1227-2, circuit 261 (OG/BK), harness side.
- Is the resistance less than 5 ohms?
Yes
INSTALL a new blower motor switch. TEST the system for normal operation.
No
REPAIR circuit 261 (OG/BK) for an open. TEST the system for normal operation.
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P4 CHECK CIRCUITS 752 (YE/RD) AND 754 (LG/WH) FOR AN OPEN
- Ignition OFF.
- Disconnect: Blower Motor Switch C294b.
- Disconnect: Blower Motor Resistor C1349.
- Measure the resistance between blower motor switch:
- C294b-4, circuit 752 (YE/RD), harness side and blower motor resistor C1349-3, circuit 752 (YE/RD), harness side.
- C294b-1, circuit 754 (LG/WH), harness side and blower motor resistor C1349-1, circuit 754 (LG/WH), harness side.
- Are the resistances less than 5 ohms?
Yes
GO to P7.
No
REPAIR the affected circuit for an open. TEST the system for normal operation.
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P5 CHECK BLOWER MOTOR RESISTOR GROUND CIRCUIT 57 (BK) FOR AN OPEN
- Ignition OFF.
- Disconnect: Blower Motor Resistor C1349.
- Measure the resistance between blower motor resistor C1349-2, circuit 57 (BK), harness side and ground.
- Are the resistance less than 5 ohms?
Yes
GO to P6.
No
REPAIR circuit 57 (BK) for an open. TEST the system for normal operation.
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P6 CHECK THE BLOWER MOTOR RESISTOR CIRCUIT 261 (OG/BK) FOR AN OPEN
- Disconnect: Blower Motor C1227.
- Measure the resistance between blower motor resistor C1349-4, circuit 261 (OG/BK), harness side and blower motor C1227-2, circuit 261 (OG/BK).
- Are the resistances less than 5 ohms?
Yes
GO to P7.
No
REPAIR circuit 261 (OG/BK) for an open. TEST the system for normal operation.
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P7 CHECK THE BLOWER MOTOR RESISTOR
- Carry out the Blower Motor Resistor component test. Resistor - Blower Motor
- 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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P8 CHECK CIRCUITS 261 (OG/BK), 752 (YE/RD) AND 754 (LG/WH) FOR A SHORT TO GROUND
- Ignition OFF.
- Disconnect: Blower Motor C1227.
- Disconnect: Blower Motor Switch C294b.
- Disconnect: Blower Motor Resistor C1349.
- Measure the resistance between ground and blower motor resistor:
- C1349-4, circuit 261 (OG/BK), harness side.
- C1349-3, circuit 752 (YE/RD), harness side.
- C1349-1, circuit 754 (LG/WH), harness side.
- Are the resistances less than 5 ohms?
Yes
INSTALL a new blower motor switch. TEST the system for normal operation.
No
REPAIR the affected circuit for a short to ground. TEST the system for normal operation.
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