Pinpoint Test W: Both Reversing Lamps Are Inoperative
Reversing Lamps
Pinpoint Tests
Pinpoint Test W: Both Reversing Lamps Are Inoperative
Refer to Wiring Diagram Set 11 (Fusion/Milan/MKZ, Fusion Hybrid/Milan Hybrid), Fuse and Relay Information for schematic and connector information. Diagrams By Number
Refer to Wiring Diagram Set 93 (Fusion/Milan/MKZ, Fusion Hybrid/Milan Hybrid), Reversing Lamps for schematic and connector information. Diagrams By Number
Normal Operation
Voltage is supplied from the Battery Junction Box (BJB) fuse 47 (10A) to the coil and switched sides of the reversing lamps relay. When the reversing lamps relay is energized, voltage is routed to the reversing lamps.
Automatic Transaxle
The PCM (2.5L or 3.0L engines) or the Transmission Control Module (TCM) (3.5L engine) monitors the transaxle gear status. When the PCM detects the transaxle in REVERSE (R), the PCM or TCM provides ground for the reversing lamps relay coil.
Manual Transaxle
The reversing lamp switch controls the coil ground side of the reversing lamps relay. When the transaxle is in REVERSE (R), the reversing lamp switch contacts close, completing the path to ground for the reversing lamps relay coil.
- DTC P1910 (Reverse Lamp Control Circuit/Open) - sets when the PCM detects no voltage on the reversing lamp 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
- PCM
- TCM
PINPOINT TEST W: BOTH 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.
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W1 CHECK THE REVERSING LAMPS RELAY
- Ignition OFF.
- Disconnect: Reversing Lamps Relay.
- Ignition ON.
- 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 W2.
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W2 CHECK FOR VOLTAGE TO THE REVERSING LAMPS RELAY COIL
- Ignition ON.
- Measure the voltage between the reversing lamps relay pin 1, circuit CBK03 (GY), BJB face side and ground.
- Is the voltage greater than 10 volts?
Yes
GO to W3.
No
VERIFY the BJB fuse 47 (10A) is OK. If OK, REPAIR circuit CBK03 (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 Diagrams By Number.
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W3 CHECK FOR VOLTAGE TO THE REVERSING LAMPS RELAY SWITCH
- Measure the voltage between the reversing lamps relay pin 3, circuit CBK03 (GY), BJB face side and ground.
- Is the voltage greater than 10 volts?
Yes
GO to W4.
No
REPAIR circuit CBK03 (GY) for an open. TEST the system for normal operation.
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W4 BYPASS THE REVERSING LAMPS RELAY
- Connect a fused jumper wire between the reversing lamps relay pin 3, circuit CBK03 (GY), BJB face side and the reversing lamps relay pin 5, circuit CLS10 (GN/BN), BJB face side.
- Do the reversing lamps illuminate?
Yes
REMOVE the jumper wire.
For vehicles with a manual transaxle, GO to W5.
For vehicles with an automatic transaxle, GO to W7.
No
REMOVE the jumper wire. REPAIR circuit CLS10 (GN/BN) for an open. TEST the system for normal operation.
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W5 CHECK FOR VOLTAGE TO THE REVERSING LAMP SWITCH
- Ignition OFF.
- Connect: Reversing Lamps Relay.
- Disconnect: Reversing Lamp Switch C169.
- Ignition ON.
- 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
GO to W6.
No
REPAIR circuit CLS28 (BU/WH) for an open. TEST the system for normal operation.
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W6 CHECK FOR VOLTAGE TO THE REVERSING LAMP SWITCH USING THE CONNECTOR GROUND
- Measure the voltage between the reversing lamp switch C169-1, circuit CLS28 (BU/WH), harness side and the reversing lamp switch C169-2, circuit GD121 (BK/YE), harness side.
- Is the voltage greater than 10 volts?
Yes
INSTALL a new reversing lamp switch. REFER to Reversing Lamp Switch Service and Repair. TEST the system for normal operation.
No
REPAIR circuit GD121 (BK/YE) for an open. TEST the system for normal operation.
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W7 CHECK FOR PCM OR TCM TR SENSOR DTCs FROM THE SELF-TEST
- Review the DTCs from the PCM (2.5L or 3.0L engine) or the TCM (3.5L engine) Key ON Engine OFF (KOEO) self-test.
- Are any TR sensor DTCs present?
Yes
REFER to Automatic Transmission/Transaxle &/or Transmission Control Systems.
No
GO to W8.
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W8 CHECK THE REVERSING LAMPS RELAY COIL GROUND CONTROLLED CIRCUIT FOR A SHORT TO VOLTAGE
- Ignition OFF.
- Disconnect: PCM C175t (2.5L or 3.0L Engine).
- Disconnect: TCM C1533 (3.5L Engine).
- Ignition ON.
- For Hybrid vehicles, measure the voltage between the PCM C175t-34, circuit CLS28 (BU/WH), harness side and ground.
- For non-Hybrid vehicles with a 2.5L or 3.0L engine, measure the voltage between the PCM C175t-33, circuit CLS28 (BU/WH), harness side and ground.
- For vehicles with a 3.5L engine, measure the voltage between the TCM C1533-13, circuit CLS28 (BU/WH), harness side and ground.
- Is any voltage present?
Yes
REPAIR circuit CLS28 (BU/WH) for a short to voltage. CLEAR the DTCs. REPEAT the self-test.
No
GO to W9.
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W9 CHECK FOR VOLTAGE TO THE PCM OR THE TCM WITH THE REVERSING LAMP RELAY CONNECTED
- Ignition OFF.
- Connect: Reversing Lamps Relay.
- Ignition ON.
- For Hybrid vehicles, measure the voltage between the PCM C175t-34, circuit CLS28 (BU/WH), harness side and ground.
- For non-Hybrid vehicles with a 2.5L or 3.0L engine, measure the voltage between the PCM C175t-33, circuit CLS28 (BU/WH), harness side and ground.
- For vehicles with a 3.5L engine, measure the voltage between the TCM C1533-13, circuit CLS28 (BU/WH), harness side and ground.
- Is the voltage greater than 10 volts?
Yes
For vehicles with a 3.5L engine, GO to W10.
For all other vehicles, GO to W11.
No
REPAIR circuit CLS28 (BU/WH) for an open. CLEAR the DTCs. REPEAT the self-test.
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W10 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 Transmission/Transaxle &/or Transmission 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.
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W11 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. REFER to Computers and 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.
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