Pinpoint Test X: The Reversing Lamps Are On Continuously
Reversing Lamps
Pinpoint Tests
Pinpoint Test X: The Reversing Lamps Are On Continuously
Refer to Wiring Diagram Set 93, Reversing Lamps for schematic and connector information. Diagrams By Number
The reversing lamps relay coil power is supplied by the Transmission Control Module (TCM) (also called a main control valve body for Expedition and a mechatronic assembly for Navigator). The reversing lamps relay coil ground is controlled by the TCM. When the reversing lamps relay is energized, voltage is routed to the reversing lamps, the auto-dimming interior mirror, and Battery Junction Box (BJB) fuse 58 (15A) (trailer tow reversing lamps). Voltage from the BJB fuse 58 (15A) is then routed to the trailer tow connector.
This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- Reversing lamps relay
- Auto-dimming interior mirror
- TCM
PINPOINT TEST X: THE REVERSING LAMPS ARE ON CONTINUOUSLY
NOTICE: Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may damage the connector.
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X1 CHECK THE REVERSING LAMPS RELAY OUTPUT
- Ignition OFF.
- Disconnect: Reversing Lamps Relay.
- Ignition ON.
- Do the reversing lamps continue to illuminate?
Yes
GO to X3.
No
GO to X2.
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X2 CHECK THE REVERSING LAMPS RELAY
- Ignition OFF.
- Substitute a known good relay.
- Apply the parking brake.
- Ignition ON.
- Select REVERSE.
- Do the reversing lamps illuminate?
Yes
REMOVE the known good relay. INSTALL a new reversing lamps relay. TEST the system for normal operation.
No
REMOVE the known good relay. GO to X5.
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X3 CHECK THE TRAILER TOW REVERSING LAMP VOLTAGE SUPPLY CIRCUIT FOR A SHORT TO VOLTAGE
- Disconnect: BJB Fuse 58 (15A).
- Do the reversing lamps continue to illuminate?
Yes
GO to X4.
No
REPAIR circuit CAT16 (GY/BN) for a short to voltage. TEST the system for normal operation.
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X4 CHECK THE AUTO-DIMMING INTERIOR MIRROR
- Ignition OFF.
- Disconnect: Interior Mirror C911, C9012 or C9039.
- Ignition ON.
- Do the reversing lamps continue to illuminate?
Yes
REPAIR circuit CLS10 (GN/BN) for a short to voltage. TEST the system for normal operation.
No
INSTALL a new auto-dimming interior mirror. REFER to Rear View Mirrors Interior Rear View Mirror. TEST the system for normal operation.
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X5 CHECK FOR CORRECT TCM OPERATION
- Disconnect the TCM connector.
- Check for:
- corrosion
- damaged pins
- pushed-out pins
- Connect the TCM connector and make sure it seats correctly.
- Operate the system and verify the concern is still present.
- Is the concern still present?
Yes
INSTALL a new TCM. REFER to Automatic Transaxle/Transmission - 6R80 Mechatronic Assembly. 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 any DTCs. REPEAT the self-test.
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