Pinpoint Test V: Both Reversing Lamps Are Inoperative
Reversing Lamps
Pinpoint Tests
Pinpoint Test V: Both Reversing Lamps Are Inoperative
Refer to Wiring Diagram Set 93, Reversing Lamps for schematic and connector information. Diagrams By Number
Normal Operation
Voltage is supplied from the Battery Junction Box (BJB) fuse 75 (5A) to the coil side of the reversing lamps relay. The reversing lamps relay switch side is supplied voltage by the BJB fuse 33 (20A). The reversing lamps relay coil ground is controlled by the PCM (automatic transmission, gasoline engine), the Transmission Control Module (TCM) (automatic transmission, diesel engine), or the reversing lamp switch (manual transmission).
For vehicles with an automatic transmission, when the transmission is in REVERSE (R), the PCM or TCM provide ground for the reversing lamps relay to energize.
For vehicles with a manual transmission, when the transmission is in REVERSE (R), the reversing lamp switch completes the ground path to energize the reversing lamps relay.
When the reversing lamps relay is energized, voltage is routed to the reversing lamps. The reversing lamps share a common ground with the rear stoplamps.
- DTC P1910 (Reverse Lamp Control Circuit/Open) - an on-demand DTC that sets when the PCM (gasoline engine, automatic transmission) or TCM (diesel engine, automatic transmission) detects an open from the reversing lamp relay coil ground control circuit.
This pinpoint test is intended to diagnose the following:
- Fuse
- Wiring, terminals or connectors
- Reversing lamps relay
- Reversing lamp switch (manual transmission)
- TCM (automatic transmission, diesel engine)
- PCM (automatic transmission, gasoline engine)
PINPOINT TEST V: BOTH REVERSING LAMPS ARE INOPERATIVE
NOTICE: It is important to install relays in their correct position in the Battery Junction Box (BJB). Installing a relay incorrectly can cause wiring shorts or damage to modules. While carrying out diagnostics on BJB relays, have only one BJB relay removed at a time. Failure to follow these instructions can result in damage to the vehicle circuitry or to controlling modules.
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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V1 CHECK THE STOPLAMP OPERATION
- Ignition OFF.
- Apply the brake pedal while observing the rear lamps.
- Do the stoplamps illuminate?
Yes
GO to V2.
No
GO to Pinpoint Test J. Pinpoint Test J: One Or More Stoplamps Are Inoperative
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V2 CHECK THE REVERSING LAMPS RELAY
- Disconnect: Reversing Lamps Relay.
- 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 V3.
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V3 CHECK FOR VOLTAGE TO THE REVERSING LAMP RELAY
- Ignition OFF.
- Measure the voltage between the reversing lamps relay pin 3, circuit SBB33 (RD), BJB face side and ground.
- Is the voltage greater than 10 volts?
Yes
GO to V4.
No
VERIFY the BJB fuse 33 (20A) is OK. If OK, REPAIR circuit SBB33 (RD) 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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V4 BYPASS THE REVERSING LAMP RELAY
- Connect a fused jumper wire between the reversing lamps relay pin 3, circuit SBB33 (RD), 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. GO to V5.
No
REMOVE the jumper wire. REPAIR circuit CLS10 (GN/BN) for an open. TEST the system for normal operation.
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V5 CHECK FOR SWITCHED VOLTAGE TO THE REVERSING LAMP RELAY
- Ignition ON.
- Measure the voltage between the reversing lamps relay pin 1, circuit CBB75 (YE/GY), BJB face side and ground.
- Is the voltage greater than 10 volts?
Yes
GO to V6.
No
VERIFY the BJB fuse 75 (5A) is OK. If OK, REPAIR circuit CBB75 (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. Diagrams By Number
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V6 CHECK THE REVERSING LAMP RELAY COIL GROUND CONTROLLED CIRCUIT FOR A SHORT TO VOLTAGE
- Ignition OFF.
- Disconnect: PCM C175b (Gasoline Engine, Manual or Automatic Transmission).
- Disconnect: TCM C1750 (Diesel Engine, Automatic Transmission).
- Disconnect: Reversing Lamp Switch C169 (Manual Transmission).
- Ignition ON.
- For vehicles with a gasoline engine, automatic transmission, measure the voltage between the PCM C175b-24, circuit CLS28 (BU/WH), harness side and ground.
- For vehicles with a diesel engine, automatic transmission, measure the voltage between the TCM C1750-23, circuit CLS28 (BU/WH), harness side and ground.
- For vehicles with a manual transmission, measure the voltage between the reversing lamp switch C169-1, circuit CLS28 (BU/WH), harness side and ground.
- Is any voltage present?
Yes
REPAIR circuit CLS28 (BU/WH) for a short to voltage. TEST the system for normal operation.
No
GO to V7.
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V7 CHECK FOR VOLTAGE TO THE REVERSING LAMP RELAY COIL GROUND CONTROLLED COMPONENT
- Ignition OFF.
- Connect: Reversing Lamps Relay.
- Ignition ON.
- For vehicles with a gasoline engine, automatic transmission, measure the voltage between the PCM C175b-24, circuit CLS28 (BU/WH), harness side and ground.
- For vehicles with a diesel engine, automatic transmission, measure the voltage between the TCM C1750-23, circuit CLS28 (BU/WH), harness side and ground.
- For vehicles with a manual transmission, 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 transmission, GO to V8.
For vehicles with an automatic transmission/gasoline engine combination, GO to V9.
For vehicles with an automatic transmission/diesel engine combination, GO to V10.
No
REPAIR circuit CLS28 (BU/WH) for an open. TEST the system for normal operation.
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V8 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 GD122 (BK), harness side.
- Is the voltage greater than 10 volts?
Yes
INSTALL a new reversing lamp switch. TEST the system for normal operation.
No
REPAIR circuit GD122 (BK) for an open. TEST the system for normal operation.
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V9 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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V10 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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