Pinpoint Test Q: The Blower Motor Is Inoperative - DATC
Climate Control System
Pinpoint Tests
Pinpoint Test Q: The Blower Motor is Inoperative - DATC
Refer to Wiring Diagram Set 55 (Escape/Mariner, Escape Hybrid/Mariner Hybrid), Automatic Climate Control System for schematic and connector information. Diagrams By Number
Normal Operation
Under normal operation, the relay coil and switch is supplied voltage. When the blower motor relay coil receives a ground from the HVAC module, the relay coil is energized and voltage is delivered to the blower motor and the blower motor control module from the relay. Ground for the motor is provided from the blower motor speed control. Ground is provided for the blower control module. The HVAC module sends a Pulse Width Modulated (PWM) signal to the blower motor speed control to control the blower speed.
- DTC B12AF (Front Blower Motor Relay Drive Circuit Shorted to Battery Voltage) - The module senses excessive voltage on the relay coil ground circuit, indicating a short directly to voltage.
- DTC B12B0 (Front Blower Motor Relay Drive Circuit Open or Shorted to Ground) - The module senses no voltage on the relay coil ground circuit, indicating an open or a short directly to ground.
- DTC B12B2 (Front Blower Motor PWM Drive Circuit Open or Shorted to Ground) - 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 relay
- Blower motor speed control module
- Blower motor
- HVAC module - Dual Automatic Temperature Control (DATC)
PINPOINT TEST Q: THE BLOWER MOTOR IS INOPERATIVE - DATC
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Q1 CHECK THE HVAC MODULE FOR DTCs
- Ignition ON.
- Check the HVAC module for DTCs.
- Are any DTCs present?
Yes
For DTC B12AF, 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 B12B0, CARRY OUT the blower motor relay component test.
If the relay tests OK, GO to Q2.
For DTC B12B2, GO to Q9.
No
GO to Q3.
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Q2 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
REPAIR circuit CH123 (VT/GN) for an open. TEST the system for normal operation.
No
VERIFY Smart Junction Box (SJB) fuse 45 (5A) is OK. If OK, REPAIR circuit CBP45 (YE) for an open. TEST the system for normal operation.
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Q3 VERIFY THE BLOWER MOTOR OPERATION
- Ignition ON.
- Press the PANEL button on the HVAC module - DATC. Adjust the blower motor setting to LO and then to HI.
- Is the blower motor inoperative in all settings?
Yes
GO to Q4.
No
GO to Pinpoint Test R. Pinpoint Test R: The Blower Motor Does Not Operate Correctly - DATC
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Q4 CHECK FOR VOLTAGE TO THE BLOWER MOTOR
- Ignition OFF.
- Disconnect: Blower Motor C2004.
- Ignition ON.
- Measure the voltage between blower motor C2004-2, circuit CH402 (YE/GN), harness side and ground.
- Is the voltage greater than 10 volts?
Yes
GO to Q5.
No
GO to Q11.
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Q5 CHECK FOR VOLTAGE TO THE BLOWER MOTOR CONTROLLER
- Ignition OFF.
- Disconnect: Blower Motor Speed Control Module C297.
- Ignition ON.
- Measure the voltage between blower motor speed control module C297-4, circuit CH402 (YE/GN), harness side and ground.
- Is the voltage greater than 10 volts?
Yes
GO to Q6.
No
REPAIR circuit CH402 (YE/GN) for an open. TEST the system for normal operation.
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Q6 CHECK CIRCUIT GD112 (BK/GN) FOR AN OPEN
- Ignition OFF.
- Measure the resistance between blower motor speed control module C297-1, circuit GD112 (BK/GN), harness side and ground.
- Is the resistance less than 5 ohms?
Yes
GO to Q7.
No
REPAIR circuit GD112 (BK/GN) for an open. TEST the system for normal operation.
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Q7 CHECK CIRCUIT VH301 (YE/BU) FOR AN OPEN
- Measure the resistance between blower motor C2004-1, circuit VH301 (YE/BU), harness side and blower motor speed control module C297-2, circuit VH301 (YE/BU), harness side.
- Is the resistance less than 5 ohms?
Yes
GO to Q8.
No
REPAIR circuit VH301 (YE/BU) for an open. TEST the system for normal operation.
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Q8 CHECK THE BLOWER MOTOR
- Connect: Blower Motor C2004.
- Connect a fused jumper lead between blower motor speed control module C297-2, circuit VH301 (YE/BU), harness side and C297-1, circuit GD112 (BK/GN), harness side.
- Ignition ON.
- Does the blower motor operate?
Yes
INSTALL a new blower motor speed control module. TEST the system for normal operation.
No
INSTALL a new blower motor. TEST the system for normal operation.
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Q9 CHECK CIRCUIT VH101 (WH/VT) FOR A SHORT TO GROUND
- Ignition OFF.
- Remove the fused jumper lead from blower motor speed control C297.
- Disconnect: HVAC Module - DATC C2356B.
- Measure the resistance between blower motor speed control module C297-3, circuit VH101 (WH/VT), harness side and ground.
- Is the resistance greater than 10,000 ohms?
Yes
GO to Q10.
No
REPAIR circuit VH101 (WH/VT) for a short to ground. TEST the system for normal operation.
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Q10 CHECK CIRCUIT VH101 (WH/VT) FOR AN OPEN
- Ignition OFF.
- Measure the resistance between blower motor speed control module C297-3, circuit VH101 (WH/VT), harness side and HVAC module - DATC C2356B-16, circuit VH101 (WH/VT), harness side.
- Is the resistance less than 5 ohms?
Yes
INSTALL a new blower motor speed control module. TEST the system for normal operation. If the blower motor is still inoperative, INSTALL a new HVAC module. TEST the system for normal operation.
No
REPAIR circuit VH101 (WH/VT) for an open. TEST the system for normal operation.
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Q11 CHECK CIRCUIT CH402 (YE/GN) FOR AN OPEN
- Ignition OFF.
- Disconnect: Blower Motor Relay.
- Measure the resistance between blower motor relay socket pin 5, circuit CH402 (YE/GN) and blower motor C2004-2, circuit CH402 (YE/GN), harness side.
- Is the resistance less than 5 ohms?
Yes
GO to Q12.
No
REPAIR circuit CH402 (YE/GN) for an open. TEST the system for normal operation.
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Q12 CHECK THE RELAY SWITCH POWER CIRCUIT FOR AN OPEN
- Measure the voltage between ground and blower motor relay socket pin 3, circuit SBB12 (GN/RD).
- Is the voltage greater than 10 volts?
Yes
GO to Q13.
No
VERIFY Battery Junction Box (BJB) fuse 12 (40A) is OK. If OK, INSTALL a new BJB. TEST the system for normal operation.
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Q13 CHECK THE HVAC 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 of this system. 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 1, circuit CBP45 (YE) and socket pin 2, circuit CH123 (VT/GN).
- Does the test lamp illuminate?
Yes
INSTALL a new blower motor relay. TEST the system for normal operation.
No
GO to Q14.
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Q14 CHECK THE HVAC MODULE CONNECTION
- Inspect the HVAC 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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