Pinpoint Test E: The Defrost System is Inoperative

WARNING: This page is about a different car, the 2013 Ford Explorer. However, it is still accessible from the selected car via links, so may be relevant.

E1 CHECK THE REAR WINDOW DEFROST GRID VOLTAGE

Disconnect: Rear Window Defrost Grid C402A .
Start the engine.
Activate the rear defrost switch.

Measure:

Positive Lead	Measurement/Action	Negative Lead
C402A-1		Ground

Is the voltage greater than 11 volts?

Yes : GO to E2 .
No : GO to E3.

E2 CHECK THE REAR WINDOW DEFROST GRID GROUND

Ignition OFF.
Disconnect: Rear Window Defrost Grid C402B .

Measure:

Positive Lead	Measurement/Action	Negative Lead
C402B-1		Ground

Is the resistance less than 3 ohms?

Yes : CARRY OUT the GRID WIRE TEST . REPAIR the rear window defrost grid or INSTALL a new rear window glass if necessary. Refer to WINDOW GRID WIRE REPAIR .
No : REPAIR the circuit.

E3 CHECK THE VOLTAGE SUPPLY TO THE REAR WINDOW DEFROST RELAY

Ignition OFF.
Disconnect: Rear Window Defrost Relay.
Ignition ON.

Measure:

Positive Lead	Measurement/Action	Negative Lead
Socket Pin 2		Ground
Socket Pin 3		Ground

Are the voltages greater than 11 volts?

Yes : GO to E4 .
No : VERIFY BJB fuses 26 (40A) and 93 (5A) are OK. If OK, REPAIR the affected circuit. If not OK, REFER to the appropriate OEM WIRING DIAGRAMS to identify the possible causes of the circuit short.

E4 CHECK THE HVAC MODULE OUTPUT

Start the engine.
Activate the rear window defrost switch.

Measure:

Positive Lead	Measurement/Action	Negative Lead
Socket Pin 1	Test Light	Socket Pin 2

Does the test light illuminate?

Yes : GO to E5 .
No : GO to E6.

E5 CHECK THE REAR WINDOW DEFROST RELAY
- Carry out the rear window defrost relay component test.
  Refer to OEM WIRING DIAGRAMS COMPONENT TESTING for component testing procedures.
Did the rear window defrost relay pass the component test?
- Yes : REPAIR open in circuit CRD06 (BN/YE).
- No : INSTALL a new rear window defrost relay.
E6 CHECK THE REAR DEFROST SWITCH (CC_SW_R_DEF) PID
- Ignition ON.
- Using a scan tool, view FCIM PIDs.
- Monitor the FCIM PID CC_SW_R_DEF while pressing and releasing the rear window defrost switch.
Does the PID agree with the rear window defrost switch status?
- Yes : GO to E7 .
- No : INSTALL a new FCIM . REFER to FRONT CONTROLS INTERFACE MODULE (FCIM) (Premium), REFER to FRONT CONTROLS INTERFACE MODULE (FCIM) (Premium Plus) or REFER to FRONT CONTROLS INTERFACE MODULE (FCIM) (Sony® Sound).

E7 CHECK THE REAR WINDOW DEFROST RELAY CONTROL CIRCUIT FOR AN OPEN

Ignition OFF.
Disconnect: HVAC Module C228A .

Measure:

Positive Lead	Measurement/Action	Negative Lead
Socket Pin 1		C228A-25

Is the resistance less than 3 ohms?

Yes : GO to E8 .
No : REPAIR the circuit.

E8 CHECK FOR CORRECT HVAC MODULE OPERATION
- Inspect the HVAC module connectors.
- Repair:
  - corrosion (install new connector or terminals - clean module pins)
  - damaged or bent pins - install new terminals/pins as necessary
  - pushed-out-pins - install new pins as necessary
- Reconnect the HVAC module connectors. Make sure they seat and latch correctly.
- Reconnect all previously disconnected components and system electrical connectors.
- Operate the system and determine if the concern is still present.
Is the concern still present?
- Yes : CHECK OASIS for any applicable TSBs . If a TSB exists for this concern, DISCONTINUE this test and FOLLOW TSB instructions. If no TSBs address this concern, INSTALL a new HVAC module. REFER to HEATING VENTILATION AIR CONDITIONING (HVAC) MODULE (Electronic Manual Temperature Control (EMTC)) or REFER to HEATING VENTILATION AIR CONDITIONING (HVAC) MODULE (Dual Automatic Temperature Control (DATC)).
- No : The system is operating correctly at this time. The concern may have been caused by module connections. ADDRESS the root cause of any connector or pin issues.