Pinpoint Test L: The Blower Motor Does Not Operate Correctly - DATC
Climate Control System
Pinpoint Test L: The Blower Motor Does Not Operate Correctly - DATC
Refer to Wiring Diagram Set 55 (Fusion/Milan/MKZ, Fusion Hybrid, Milan Hybrid, MKZ Hybrid), Automatic Climate Control System for schematic and connector information. Diagrams By Number
Normal Operation
Under normal operation, the blower motor relay coil receives a ground from the HVAC module through circuit CH123 (VT/GN). The coil receives ignition voltage through circuit CBP45 (YE). Voltage is supplied to the relay switch contact through circuit SBB06 (BN/RD). When the relay coil is energized, voltage is delivered to the blower motor speed control through circuit CH402 (YE/GN). Ground for the blower motor speed control is provided by circuit GD115 (BK/GY). Voltage for the motor is provided through circuit VH301 (YE/BU) from the blower motor speed control. Ground for the motor is provided through circuit VH219 (GY) from the blower motor speed control. The HVAC module sends a Pulse-Width Modulation (PWM) signal to the blower motor speed control through circuit VH101 (WH/VT) to control the blower speed.
- 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.
- DTC B10B9:14 (Blower Control: Circuit Short to Ground or Open) - The module senses no voltage on the blower motor control PWM circuit, indicating an open or a short directly to ground.
This pinpoint test is intended to diagnose the following:
- Fuse(s)
- Wiring, terminals or connectors
- Blower motor speed control
- HVAC module - Dual Automatic Temperature Control (DATC)
PINPOINT TEST L: THE BLOWER MOTOR DOES NOT OPERATE CORRECTLY - DATC
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L1 CHECK THE HVAC MODULE FOR DTCs
- Ignition ON.
- Check the HVAC module for DTCs.
- Are any DTCs present?
Yes
For DTC B10AF:14, REPAIR circuit CH123 (VT/GN) for a short to ground. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
For DTC B10B9:14, REPAIR circuit VH101 (WH/VT) for a short to ground. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
No
GO to L2.
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L2 VERIFY THE BLOWER MOTOR OPERATION
- Ignition ON.
- Press the panel button on the HVAC module. Adjust the blower motor setting to LO and then to HI.
- Does the blower motor operate at any setting?
Yes
If the blower motor operates always in HI, GO to L4.
If the blower motor is always ON, CARRY OUT the blower motor relay component test.
If the relay tests OK, GO to L3.
No
GO to Pinpoint Test K. Pinpoint Test K: The Blower Motor is Inoperative
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L3 CHECK CIRCUIT VH301 (YE/BU) FOR A SHORT TO VOLTAGE
- Ignition OFF.
- Disconnect: Blower Motor Speed Control C271.
- Disconnect: Blower Motor C288.
- Ignition ON.
- Measure the voltage between ground and blower motor speed control C271-E, circuit VH301 (YE/BU), harness side.
- Is any voltage present?
Yes
REPAIR circuit VH301 (YE/BU) for a short to voltage. TEST the system for normal operation.
No
GO to L5.
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L4 CHECK CIRCUIT VH219 (GY) FOR A SHORT TO GROUND
- Ignition OFF.
- Measure the resistance between ground and blower motor speed control C271-D, circuit VH219 (GY), harness side.
- Is the resistance greater than 10,000 ohms?
Yes
INSTALL a new blower control. TEST the system for normal operation. If the condition returns, GO to L5.
No
REPAIR circuit VH219 (GY) for a short to voltage. TEST the system for normal operation.
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L5 CHECK THE MODULE CONNECTION
- Inspect the module connectors for:
- corrosion.
- pushed-out terminals.
- damaged terminals.
- Connect and correctly seat all the HVAC module connectors.
- Clear the DTCs.
- Operate the system and verify the concern is still present.
- Is the concern still present?
Yes
INSTALL a new HVAC module. TEST the system for normal operation.
No
The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
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