Pinpoint Test E: The Heated Exterior Mirror Is Inoperative

Rear View Mirrors - Exterior

Pinpoint Tests

Pinpoint Test E: The Heated Exterior Mirror is Inoperative

Refer to Wiring Diagram Set 56 (Fusion/Milan/MKZ, Fusion Hybrid/Milan Hybrid), Heated Windows for schematic and connector information. Diagrams By Number

Refer to Wiring Diagram Set 124 (Fusion/Milan/MKZ, Fusion Hybrid/Milan Hybrid), Power Mirrors for schematic and connector information. Diagrams By Number

Normal Operation

Under normal operation, the LH and RH exterior mirror glass receives power from Power Distribution Box (PDB) fuse 38 (10A) and through circuit CBB38 (GY/BU), when the rear window defrost system is on. Ground is supplied to the LH heated exterior mirror glass through circuit GD126 (BK/WH) and to the RH heated exterior mirror glass through circuit GD139 (BK/YE).

This pinpoint test is intended to diagnose the following:
- Fuse
- Wiring, terminals or connectors
- Exterior mirror glass
- Exterior mirror



PINPOINT TEST E: THE HEATED EXTERIOR MIRROR IS INOPERATIVE

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E1 CHECK THE OPERATION OF THE REAR WINDOW DEFROST SYSTEM


- Ignition ON.
- Press the rear window defrost switch to the ON position.
- Place a hand on the rear window to verify that the rear window heats up.
- Does the rear window defrost system operate?

Yes
GO to E2.

No
REFER to Windows and Glass to diagnose the rear window defrost system.

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E2 CHECK THE VOLTAGE TO THE EXTERIOR MIRRORS


- Ignition OFF.
- Disconnect: LH Exterior Mirror C517 (without memory mirrors)/C522 (with memory mirrors) or RH Exterior Mirror C625 (without memory mirrors)/C626 (with memory mirrors).
- Ignition ON.
- Press the rear window defrost switch to the ON position.
- Without memory mirrors: Measure the voltage between ground and inoperative exterior mirror:
- LH: C517-5, circuit CBB38 (GY/BU), harness side.
- RH: C625-5, circuit CBB38 (GY/BU0), harness side.




- With memory mirrors: Measure the voltage between ground and inoperative exterior mirror:
- LH: C522-6, circuit CBB38 (BU/OG), harness side.
- RH: C626-6, circuit CBB38 (GY/BU), harness side.




- Is the voltage greater than 10 volts?

Yes
GO to E3.

No
VERIFY that PDB fuse 38 (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 Diagrams By Number. TEST the system for normal operation.

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E3 CHECK THE EXTERIOR REAR VIEW MIRROR GROUND CIRCUIT FOR AN OPEN


- Ignition OFF.
- Without memory mirrors: Measure the resistance between ground and inoperative exterior mirror:
- LH: C517-6, circuit GD126 (BK/WH), harness side.
- RH: C625-6, circuit GD139 (BK/YE), harness side.




- With memory mirrors: Measure the resistance between ground and inoperative exterior mirror:
- LH: C522-7, circuit GD126 (BK/WH), harness side.
- RH: C626-7, circuit GD139 (BK/YE), harness side.




- Is the resistance less than 5 ohms?

Yes
CHECK the LH or RH exterior mirror jumper harness between the vehicle harness and the exterior mirror glass for open circuits and damaged or pushed-out pins. If the jumper harness is not OK, REPAIR the jumper harness. If the jumper harness cannot be repaired, INSTALL a new LH or RH exterior mirror. REFER to Exterior Mirror Exterior Mirror. If the jumper harness is OK, INSTALL a new LH or RH exterior mirror glass. REFER to Exterior Mirror Glass Exterior Mirror Glass. TEST the system for normal operation.

No
REPAIR the circuit. TEST the system for normal operation.

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