Pinpoint Test F: The Defrost System is Inoperative
Glass, Frames and Mechanisms
Pinpoint Tests
Pinpoint Test F: The Defrost System is Inoperative
Refer to Wiring Diagram Set 56 (Escape/Mariner, Escape Hybrid/Mariner Hybrid), Heated Window for schematic and connector information. Diagrams By Number
Normal Operation
The rear window defrost relay receives power from the Battery Junction Box (BJB) fuse 35 (10A) on circuit CBB35 (YE/GY). When the rear window defrost switch is pressed to the ON position, the HVAC module activates the rear window defrost relay by grounding circuit CH122 (WH/OG). When activated, the rear window defrost relay supplies 12 volts to the rear window defrost grid on circuit CRD06 (BN/YE). The rear window defrost grid is grounded through circuit GD149 (BK/GY).
The HVAC module will deactivate the rear window defrost relay when one of the following conditions is met:
- The rear window defrost switch is pressed when the feature is active.
- The ignition switch state is changed from ON to OFF/LOCK.
- The 15-minute timing function is complete.
For Escape Hybrid equipped with navigation only, the rear window defrost switch is integral to the Front Controls Interface Module (FCIM). When the defrost switch is pressed, the FCIM sends the defrost request message to the HVAC module over the Controller Area Network (CAN). When the request is received, the HVAC module activates the rear window defrost relay.
This pinpoint test is intended to diagnose the following:
- Fuse
- Wiring, terminals or connectors
- Rear window defrost relay
- Rear window defrost switch (integral to the HVAC module)
- Rear window defrost grid
- HVAC module
- FCIM
PINPOINT TEST F: THE DEFROST SYSTEM IS INOPERATIVE
NOTICE: Use the correct probe adapter(s) from the Flex Probe Kit when making measurements. Failure to use the correct probe adapter(s) may damage the connector.
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F1 CHECK CIRCUIT CRD06 (BN/YE) FOR VOLTAGE
- Disconnect: Rear Window Defrost Grid C402A.
- Start the engine.
- Activate the rear window defrost switch.
- Measure the voltage between rear window defrost grid C402A-1, circuit CRD06 (BK), harness side and ground.
- Is the voltage greater than 10 volts?
Yes
GO to F2.
No
VERIFY BJB fuse 2 (30A) is OK. If OK, GO to F3.
If not OK, Refer to the Wiring Diagrams to identify the possible causes of the circuit short. Diagrams By Number
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F2 CHECK THE GRID GROUND CIRCUIT FOR AN OPEN
- Ignition OFF.
- Disconnect: Rear Window Defrost C402B.
- Measure the resistance between rear window defrost grid C402B-1, circuit GD149 (BK/GY), harness side and ground.
- Is the resistance less than 5 ohms?
Yes
CARRY OUT the Grid Wire Component Test. REPAIR the rear window defrost grid or INSTALL a new liftgate glass as necessary. REFER to Window Grid Wire Repair Window Grid Wire Repair or Window Glass - Liftgate Service and Repair. TEST the system for normal operation. Component Tests and General Diagnostics
No
REPAIR the circuit. CLEAR all DTCs. TEST the system for normal operation.
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F3 CHECK THE REAR WINDOW DEFROST RELAY FEED CIRCUITS FOR VOLTAGE
- Ignition OFF.
- Disconnect: Rear Window Defrost Relay.
- Ignition ON.
- Measure the voltage between rear window defrost relay socket pin 3, circuit CBB35 (YE/GY) and ground; and between rear window defrost socket relay socket pin 1, circuit CBB35 (YE/GY) and ground.
- Are the voltages greater than 10 volts?
Yes
GO to F4.
No
VERIFY BJB fuse 35 (10A) is OK. If OK, REPAIR the circuit.
If not OK, Refer to the Wiring Diagrams to identify the possible causes of the circuit short. CLEAR all DTCs. TEST the system for normal operation. Diagrams By Number
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F4 CHECK THE HVAC MODULE
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.
- Start the engine.
- Activate the rear window defrost switch.
- Connect a 12-volt incandescent test light between rear window defrost relay socket pin 2, circuit CH122 (WH/OG) and rear window defrost relay socket pin 1, circuit CBB35 (YE/GY).
- Does the test light illuminate?
Yes
GO to F5.
No
For Escape Hybrid equipped with navigation only, GO to F6. For all other vehicles, GO to F7.
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F5 CHECK THE REAR WINDOW DEFROST RELAY
- Ignition OFF.
- Carry out the rear window defrost relay component test.
- Did the rear window defrost relay pass the component test?
Yes
REPAIR open in circuit CRD06 (BN/YE). CLEAR the DTCs. TEST the system for normal operation.
No
INSTALL a new rear window defrost relay. CLEAR all DTCs. TEST the system for normal operation.
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F6 CHECK THE REAR WINDOW DEFROST SWITCH (CC_SW_R_DEF) PID
- Ignition ON.
- Enter the following diagnostic mode on the scan tool: DataLogger - FCIM.
- Monitor the FCIM CC_SW_R_DEF PID while pressing and releasing the rear window defrost switch.
- Does the PID agree with the rear window defrost switch status?
Yes
GO to F7.
No
INSTALL a new FCIM. CLEAR the DTCs. TEST the system for normal operation.
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F7 CHECK CIRCUIT CH122 (WH/OG) FOR AN OPEN
- Ignition OFF.
- Disconnect: HVAC Module - Electronic Manual Temperature Control (EMTC) C2357A or HVAC Module - Dual Automatic Temperature Control (DATC) C2356A.
- Measure the resistance between rear window defrost relay socket pin 2, circuit CH122 (WH/OG) and HVAC module EMTC C2357A-3, HVAC module - DATC C2356A-3 (non-hybrid) or C2356A-12 (hybrid), circuit CH122 (WH/OG), harness side.
- Is the resistance less than 5 ohms?
Yes
GO to F8.
No
REPAIR the circuit. CLEAR all DTCs. TEST the system for normal operation.
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F8 CHECK FOR CORRECT HVAC MODULE OPERATION
- Disconnect all the HVAC module connectors.
- Check for:
- corrosion.
- pushed-out pins.
- Connect all the HVAC module connectors and make sure they seat correctly.
- Operate the system and verify the concern is still present.
- Is the concern still present?
Yes
INSTALL a new HVAC module. REFER to Body Control Systems. 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 all DTCs. TEST the system for normal operation.
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