Pinpoint Test V: The Reversing Lamps Are Inoperative
Reversing Lamps
Pinpoint Tests
Pinpoint Test V: The Reversing Lamps Are Inoperative
Refer to Wiring Diagram Set 93 (Escape/Mariner, Escape Hybrid/Mariner Hybrid), Reversing Lamps for schematic and connector information. Diagrams By Number
Normal Operation
Voltage is supplied from the Battery Junction Box (BJB) fuse 27 (10A) (except Hybrid) or fuse 28 (15A) (Hybrid) to the coil side of the reversing lamps relay through circuit CBK03 (GY) (except Hybrid) or circuit CBK02 (GN) (Hybrid). The reversing lamps relay switch side is supplied voltage by the BJB fuse 35 (10A) through circuit CBB35 (YE/GY). The reversing lamps relay coil ground is controlled by the PCM (automatic transaxle) or the reversing lamp switch (manual transaxle) through circuit CLS28 (BU/WH).
For vehicles with an automatic transaxle, when the transaxle is in REVERSE (R), the PCM provides ground to energize the reversing lamps relay.
For vehicles with a manual transaxle, when the transaxle is in REVERSE (R), the reversing lamps switch completes the path to ground through circuit GD120 (BK/GN) to energize the reversing lamps relay.
When the reversing lamps relay is energized, voltage is routed to the reversing lamps through circuit CBB07 (GN/BU). The reversing lamps share a common ground through circuit GD182 (BK/GY).
- DTC P1910 (Reverse Lamp Control Circuit/Open) - sets when the PCM detects no voltage from the reversing lamps relay coil ground control circuit (if the coil voltage supply circuit or the coil ground control circuit is open).
This pinpoint test is intended to diagnose the following:
- Fuse
- Wiring, terminals or connectors
- Reversing lamps relay
- Reversing lamp switch (manual transaxle)
- PCM (automatic transaxle)
PINPOINT TEST V: THE REVERSING LAMPS ARE INOPERATIVE
NOTICE: Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may damage the connector.
NOTE: Failure to disconnect the battery when instructed will result in false resistance readings. Refer to Battery.
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V1 CHECK FOR VOLTAGE TO THE REVERSING LAMPS
- Ignition OFF.
- Disconnect: LH Reversing Lamp C451.
- Apply the parking brake.
- Ignition ON.
- Select REVERSE.
- Measure the voltage between the LH reversing lamp C451-2, circuit CBB07 (GN/BU), harness side and ground.
- Is the voltage greater than 10 volts?
Yes
REPAIR circuit GD182 (BK/GY) for an open. TEST the system for normal operation.
No
GO to V2.
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V2 CHECK THE REVERSING LAMPS RELAY
- Select PARK.
- Connect: LH Reversing Lamp C451.
- Disconnect: Reversing Lamps Relay.
- Substitute a known good relay and recheck the reversing lamps operation.
- Do the reversing lamps operate correctly?
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 V3.
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V3 CHECK FOR VOLTAGE TO THE REVERSING LAMPS RELAY
- Ignition ON.
- Measure the voltage between the reversing lamps relay pin 3, circuit CBB35 (YE/GY), BJB face side and ground.
- Is the voltage greater than 10 volts?
Yes
GO to V4 .
No
VERIFY the BJB fuse 35 (10A) is OK. If OK, REPAIR circuit CBB35 (YE/GY) for an open. TEST the system for normal operation. If not OK, REFER to the Wiring Diagrams to identify the possible causes of the circuit short.
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V4 CHECK THE REVERSING LAMPS RELAY OUTPUT CIRCUIT FOR AN OPEN
- Connect a fused jumper wire between the reversing lamps relay pin 3, circuit CBB35 (YE/GY), BJB face side and the reversing lamps relay pin 5, circuit CBB07 (GN/BU), BJB face side.
- Do the reversing lamps illuminate?
Yes
REMOVE the jumper wire. GO to V5.
No
REMOVE the jumper wire. REPAIR circuit CBB07 (GN/BU) for an open. TEST the system for normal operation.
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V5 CHECK FOR VOLTAGE TO THE REVERSING LAMPS RELAY COIL
- Measure the voltage between the reversing lamps relay pin 1, circuit CBK03 (GY) (except Hybrid) or circuit CBK02 (GN) (Hybrid), BJB face side and ground.
- Is the voltage greater than 10 volts?
Yes
GO to V6.
No
VERIFY the BJB fuse 27 (10A) (except Hybrid) or fuse 28 (15A) (Hybrid) is OK. If OK, REPAIR circuit CBK03 (GY) (except Hybrid) or circuit CBK02 (GN) (Hybrid) for an open.
TEST the system for normal operation. If not OK, REFER to the Wiring Diagrams to identify the possible causes of the circuit short.
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V6 CHECK CIRCUIT CLS28 (BU/WH) FOR AN OPEN
- Ignition OFF.
- Connect: Reversing Lamps Relay.
- Disconnect: Reversing Lamp Switch C169 (Manual Transaxle).
- Disconnect: PCM C175t (Automatic Transaxle).
- Ignition ON.
- For non-Hybrid vehicles with an automatic transaxle, measure the voltage between the PCM C175t-33, circuit CLS28 (BU/WH), harness side and ground.
- For Hybrid vehicles with an automatic transaxle, measure the voltage between the PCM C175t-34, circuit CLS28 (BU/WH), harness side and ground.
- For vehicles with a manual transaxle, measure the voltage between the reversing lamp switch C169-1, circuit CLS28 (BU/WH), harness side and ground.
- Is the voltage greater than 10 volts?
Yes
For vehicles with a manual transaxle, GO to V7.
For vehicles with an automatic transaxle, GO to V8.
No
REPAIR circuit CLS28 (BU/WH) for an open. TEST the system for normal operation.
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V7 CHECK CIRCUIT GD120 (BK/GN) FOR AN OPEN
- Ignition OFF.
- Disconnect: Negative Battery Cable.
- Measure the resistance between the reversing lamp switch C169-2, circuit GD120 (BK/GN), harness side and ground.
- Is the resistance less than 5 ohms?
Yes
INSTALL a new reversing lamp switch. REFER to Reversing Lamp Switch Service and Repair. TEST the system for normal operation.
No
REPAIR circuit GD120 (BK/GN) for an open. TEST the system for normal operation.
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V8 CHECK FOR CORRECT PCM OPERATION
- Disconnect all the PCM connectors.
- Check for:
- corrosion
- damaged pins
- pushed-out pins
- Connect all the PCM 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 PCM. 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.
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