Pinpoint Test K: The Blower Motor is Inoperative
Climate Control System
Pinpoint Test K: The Blower Motor is Inoperative
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 SBB35 (BU/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.
This pinpoint test is intended to diagnose the following:
- Fuse(s)
- Wiring, terminals or connectors
- Blower motor relay
- Blower motor speed control
- HVAC module - Dual Automatic Temperature Control (DATC)
- Blower motor
PINPOINT TEST K: THE BLOWER MOTOR IS INOPERATIVE
-------------------------------------------------
K1 CHECK THE HVAC MODULE FOR DTCs
- Ignition ON.
- Check the HVAC module for DTCs.
- Are any DTCs present?
Yes
For DTC B10AF:12, REPAIR circuit CH123 (VT/GN) for a short to voltage. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
For DTC B10AF:14, CARRY OUT the Blower Motor Relay component test.
If the relay tests OK, GO to K2.
For DTC B10B9:14, GO to K4.
For DTC B10B9:12, REPAIR circuit VH101 (VT/WH) for a short to voltage. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
No
GO to K6.
-------------------------------------------------
K2 CHECK THE RELAY COIL SUPPLY VOLTAGE
- Ignition OFF.
- Disconnect: Blower Motor Relay.
- Ignition ON.
- Measure the voltage between blower motor relay socket pin 1, circuit CBP45 (YE) and ground.
- Is the voltage greater than 10 volts?
Yes
GO to K3.
No
VERIFY Smart Junction Box (SJB) fuse 45 (5A) is OK. If OK, REPAIR circuit CBP45 (YE) for an open. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation. If not OK, Refer to the Wiring Diagrams to identify the possible causes of the circuit short. Diagrams By Number
-------------------------------------------------
K3 CHECK CIRCUIT CH123 (VT/GN) FOR AN OPEN
- Ignition OFF.
- Disconnect: HVAC Module - DATC C2356a.
- Measure the resistance between blower motor relay socket pin 2, circuit CH123 (VT/GN) and HVAC module - DATC C2356a-24, circuit CH123 (VT/GN), harness side.
- Is the resistance less than 5 ohms?
Yes
GO to K17.
No
REPAIR circuit CH123 (VT/GN) for an open. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
-------------------------------------------------
K4 CHECK CIRCUIT VH101 (WH/VT) FOR AN OPEN
- Ignition OFF.
- Disconnect: Blower Motor Speed Control C271.
- Disconnect: HVAC Module - DATC C2356a.
- Measure the resistance between blower motor control C271-B, circuit VH101 (WH/VT), harness side and HVAC module - DATC C2356a-14, circuit VH101 (WH/VT), harness side.
- Is the resistance less than 5 ohms?
Yes
GO to K5.
No
REPAIR circuit VH101 (WH/VT) for an open. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
-------------------------------------------------
K5 CHECK CIRCUIT VH101 (WH/VT) FOR GROUND SIGNAL
- Connect: HVAC Module - DATC C2356a.
- Ignition ON.
- Press the PANEL button on the HVAC module. Adjust the blower motor setting to HI.
- Measure the voltage between blower motor speed control C271-B, circuit VH101 (WH/VT), harness side and blower motor speed control C271-C, circuit CH402 (YE/GN), harness side.
- Is the voltage greater than 10 volts?
Yes
GO to K16.
No
GO to K17.
-------------------------------------------------
K6 CHECK FOR VOLTAGE TO THE BLOWER MOTOR
- Ignition OFF.
- Disconnect: Blower Motor C288.
- Ignition ON.
- Measure the voltage between blower motor C288-A, circuit VH219 (GY), harness side and blower motor C288-B, circuit VH301 (YE/BU), harness side.
- Is the voltage greater than 10 volts?
Yes
INSTALL a new blower motor. TEST the system for normal operation.
No
GO to K7.
-------------------------------------------------
K7 CHECK FOR VOLTAGE TO THE BLOWER MOTOR CONTROLLER
- Ignition OFF.
- Disconnect: Blower Motor Speed Control C271.
- Ignition ON.
- Press the PANEL button on the HVAC module.
- Measure the voltage between blower motor speed control C271-C, circuit CH402 (YE/GN), harness side and ground.
- Is the voltage greater than 10 volts?
Yes
GO to K8.
No
GO to K14.
-------------------------------------------------
K8 CHECK CIRCUIT GD115 (BK/GY) FOR AN OPEN
- Ignition OFF.
- Measure the resistance between blower motor speed control C271-A, circuit GD115 (BK/GY), harness side and ground.
- Is the resistance less than 5 ohms?
Yes
GO to K9.
No
REPAIR circuit GD115 (BK/GY) for an open. TEST the system for normal operation.
-------------------------------------------------
K9 CHECK CIRCUIT VH101 (WH/VT) FOR GROUND SIGNAL
- Ignition ON.
- Press the PANEL button on the HVAC module. Adjust the blower motor setting to HI.
- Measure the voltage between blower motor speed control C271-B, circuit VH101 (WH/VT), harness side and blower motor speed control C271-C, circuit CH402 (YE/GN), harness side.
- Is the voltage greater than 10 volts?
Yes
GO to K10.
No
GO to K17.
-------------------------------------------------
K10 CHECK CIRCUITS VH219 (GY) AND VH301 (YE/BU) FOR AN OPEN
- Measure the resistance between the blower motor connector, harness side and blower motor speed control, harness side using the following chart.
- Are the resistances less than 5 ohms?
Yes
GO to K11.
No
REPAIR circuit VH219 (GY) or VH301 (YE/BU) for an open. TEST the system for normal operation.
-------------------------------------------------
K11 CHECK CIRCUITS VH219 (GY) AND VH301 (YE/BU) FOR A SHORT TOGETHER
- Measure the resistance between blower motor C288-A, circuit VH219 (GY), harness side and blower motor C288-B, circuit VH301 (YE/BU), harness side.
- Is the resistance greater than 10,000 ohms?
Yes
GO to K12.
No
REPAIR circuits VH219 (GY) and VH301 (YE/BU) for a short together. TEST the system for normal operation.
-------------------------------------------------
K12 CHECK CIRCUIT VH219 (GY) FOR A SHORT TO GROUND
- Measure the resistance between ground and blower motor C288-A, circuit VH219 (GY), harness side.
- Is the resistance greater than 10,000 ohms?
Yes
GO to K13.
No
REPAIR circuit VH219 (GY) for a short to ground. TEST the system for normal operation.
-------------------------------------------------
K13 CHECK CIRCUIT VH301 (YE/BU) FOR A SHORT TO VOLTAGE
- Ignition ON.
- Measure the voltage between ground and blower motor C288-B, 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 K16.
-------------------------------------------------
K14 CHECK THE RELAY SWITCH POWER CIRCUIT FOR AN OPEN
- Measure the voltage between blower motor relay socket pin 3, circuit SBB35 (BU/RD) and ground.
- Is the voltage greater than 10 volts?
Yes
GO to K15.
No
VERIFY Battery Junction Box (BJB) fuse 35 (40A) is OK. If OK, REPAIR circuit SBB35 (BU/RD) for an open. TEST the system for normal operation. If not OK, Refer to the Wiring Diagrams to identify the possible causes of the circuit short. Diagrams By Number
-------------------------------------------------
K15 CHECK THE MODULE OUTPUT
NOTICE: The following step uses a test light to simulate 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 ON.
- With the engine running, connect a 12-volt test lamp between blower motor relay socket pin 2, circuit CH123 (VT/GN) and socket pin 1, circuit CBP45 (YE).
- Does the test lamp illuminate?
Yes
CARRY OUT the blower motor relay component test.
If the relay tests OK, REPAIR circuit CH402 (YE/GN) for a short to ground. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
No
GO to K17.
-------------------------------------------------
K16 CHECK THE BLOWER MOTOR SPEED CONTROL CONNECTION
- Clear the DTCs.
- Disconnect the blower motor speed control connector.
- Check for:
- corrosion.
- pushed-out terminals.
- damaged terminals.
- Connect and correctly seat the connector.
- Carry out the HVAC On-Demand Self Test.
- Operate the system and verify the concern is still present.
- Is the concern still present?
Yes
INSTALL a new blower motor speed control. REFER to Climate Control Service and Repair. CLEAR the DTCs. 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. TEST the system for normal operation.
-------------------------------------------------
K17 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.
-------------------------------------------------