Pinpoint Test R: The Blower Motor Does Not Operate Correctly - EMTC
Climate Control System
Pinpoint Test R: The Blower Motor Does Not Operate Correctly - EMTC
Refer to Wiring Diagram Set 54 (Fusion/Milan/MKZ, Fusion Hybrid, Milan Hybrid, MKZ Hybrid), Manual Climate Control System for schematic and connector information. Diagrams By Number
Normal Operation
Under normal operation, the blower motor is provided ground from the blower resistor through circuit CH426 (YE/OG). The resistor gets a ground from circuit GD115 (BK/GY) in the lowest blower setting. In MED-LO and MED-HI the resistor gets ground from the blower motor switch through circuit CH428 (GN/WH) or CH429 (GY/BN), depending on selected speed. In HI, the blower motor is grounded directly through the blower motor switch from circuit CH426 (YE/OG) to circuit GD115 (BK/GY). The blower switch receives its ground from circuit GD115 (BK/GY).
- DTC B10AF:14 (Blower Fan Relay: Circuit Short to Ground or Open) - The module senses no voltage on the relay coil ground circuit, indicating an open or a short directly to ground.
This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- Blower motor resistor
- HVAC module - Electronic Manual Temperature Control (EMTC)
PINPOINT TEST R: THE BLOWER MOTOR DOES NOT OPERATE CORRECTLY - EMTC
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R1 CHECK THE HVAC MODULE FOR DTCs
- Ignition ON.
- Check the HVAC module for DTCs.
- Is DTC B10AF:14 present?
Yes
REPAIR circuit CH123 (VT/GN) for a short to ground. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
No
GO to R2.
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R2 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 setting only, GO to R3.
If the blower motor does not operate in LO setting only, GO to R4.
If the blower motor does not operate in MED-LO or MED-HI setting only, GO to R5.
If the blower motor operates in HI setting only, GO to R7.
If the blower motor operates in LO setting only, GO to R8.
For all other symptoms, GO to R9.
No
GO to Pinpoint Test Q. Pinpoint Test Q: The Blower Motor is Inoperative - EMTC
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R3 CHECK CIRCUIT CH426 (YE/OG) FOR AN OPEN
- Ignition OFF.
- Disconnect: HVAC Module - EMTC C2357b.
- Disconnect: Blower Motor C288.
- Measure the resistance between HVAC module - EMTC C2357b-2, circuit CH426 (YE/OG), harness side and blower motor C288-B, circuit CH426 (YE/OG), harness side.
- Is the resistance less than 5 ohms?
Yes
INSTALL a new HVAC module. TEST the system for normal operation.
No
REPAIR circuit CH426 (YE/OG) for an open. TEST the system for normal operation.
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R4 CHECK BLOWER MOTOR RESISTOR GROUND CIRCUIT GD115 (BK/GY) FOR AN OPEN
- Ignition OFF.
- Disconnect: Blower Motor Resistor C1228.
- Measure the resistance between blower motor resistor C1228-D, circuit GD115 (BK/GY), harness side and ground.
- Is the resistance less than 5 ohms?
Yes
INSTALL a new blower motor resistor. REFER to Climate Control Service and Repair. TEST the system for normal operation.
No
REPAIR circuit GD115 (BK/GY) for an open. TEST the system for normal operation.
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R5 CHECK CIRCUIT CH428 (GN/WH) OR CH429 (GY/BN) FOR GROUND
NOTICE: The following step uses a test light to stimulate normal circuit loads. Use only the test light recommended in the Special Tools table at the beginning or equivalent. To avoid connector terminal damage, use the Flex Probe kit for the test light probe connection to the vehicle. Do not use the test light probe directly on any connector.
- Ignition OFF.
- Disconnect: Blower Motor Resistor C1228.
- Ignition ON.
For MED-LO inoperative.
- For MED-LO inoperative: With the blower motor switch in the MED-LO speed position, connect a 12-volt test lamp between blower motor resistor C1228-C, circuit CH426 (YE/OG), harness side and blower motor resistor C1228-A, circuit CH428 (GN/WH), harness side.
For MED-HI inoperative.
- For MED-HI inoperative: With the blower motor switch in the MED-HI speed position, connect a 12-volt test lamp between blower motor resistor C1228-C, circuit CH426 (YE/OG), harness side and blower motor resistor C1228-B, circuit CH429 (GY/BN), harness side.
- Does the test lamp illuminate?
Yes
INSTALL a new blower motor resistor. TEST the system for normal operation.
No
GO to R6.
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R6 CHECK CIRCUIT CH428 (GN/WH) OR CH429 (GY/BN) FOR AN OPEN
- Ignition OFF.
- Disconnect: HVAC Module - EMTC C2357b.
For MED-LO inoperative.
- For MED-LO inoperative, measure the resistance between HVAC module - EMTC C2357b-4, circuit CH428 (GN/WH), harness side and blower motor resistor C1228-A, circuit CH428 (GN/WH), harness side.
For MED-HI inoperative.
- For MED-HI inoperative, measure the resistance between HVAC module - EMTC C2357b-3, circuit CH429 (GY/BN), harness side and blower motor resistor C1228-B, circuit CH429 (GY/BN), harness side.
- Is the resistance less than 5 ohms?
Yes
CARRY OUT the Blower Motor Resistor component test. If the resistor tests OK, INSTALL a new blower motor switch. TEST the system for normal operation. Component Tests
No
REPAIR circuit CH428 (GN/WH) or CH429 (GY/BN) for an open. TEST the system for normal operation.
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R7 CHECK CIRCUIT CH426 (YE/OG) FOR AN OPEN
- Ignition OFF.
- Disconnect: Blower Motor Resistor C1228.
- Disconnect: Blower Motor C288.
- Measure the resistance between blower motor resister C1228-C, circuit CH426 (YE/OG), harness side and blower motor C288-B, circuit CH426 (YE/OG), harness side.
- Is the resistance less than 5 ohms?
Yes
INSTALL a new blower motor resistor. TEST the system for normal operation.
No
REPAIR circuit CH426 (YE/OG) for an open. TEST the system for normal operation.
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R8 CHECK THE BLOWER MOTOR SWITCH CIRCUIT GD115 (BK/GY) FOR AN OPEN
- Measure the resistance between HVAC Module - EMTC C2357b-1, circuit GD115 (BK/GY), harness side and ground.
- Is the resistance less than 5 ohms?
Yes
INSTALL a new HVAC module. TEST the system for normal operation.
No
REPAIR circuit GD115 (BK/GY) for an open. TEST the system for normal operation.
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R9 CHECK CIRCUITS CH426 (YE/OG), CH428 (GN/WH) AND CH429 (GY/BN) FOR A SHORT TO GROUND
- Ignition OFF.
- Disconnect: Blower Motor C288.
- Disconnect: Blower Motor Resistor C1228.
- Disconnect: HVAC Module - EMTC C2357b.
- Measure the resistance between ground and blower motor resistor:
- C1228-A, circuit CH428 (GN/WH), harness side.
- C1228-C, circuit CH426 (YE/OG), harness side.
- C1228-B, circuit CH429 (GY/BN), harness side.
- Are the resistances greater than 10,000 ohms?
Yes
GO to R10.
No
REPAIR the affected circuit for a short to ground. TEST the system for normal operation.
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R10 CHECK THE BLOWER MOTOR CIRCUITS FOR SHORTS TOGETHER
- Measure the resistance between blower motor resistor:
- C1228-A, circuit CH428 (GN/WH), harness side and C1228-C, circuit CH426 (YE/OG), harness side.
- C1228-A, circuit CH428 (GN/WH), harness side and C1228-B, circuit CH429 (GY/BN), harness side.
- C1228-C, circuit CH426 (YE/OG), harness side and C1228-B, circuit CH429 (GY/BN), harness side.
- Are the resistances greater than 10,000 ohms?
Yes
CARRY OUT the Blower Motor Resistor component test. If the resistor tests OK, INSTALL a new HVAC module. TEST the system for normal operation. Component Tests
No
REPAIR the affected circuits. TEST the system for normal operation.
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