Pinpoint Test R: Both Reversing Lamps Are Inoperative
Reversing Lamps
Pinpoint Tests
Pinpoint Test R: Both Reversing Lamps Are Inoperative
Refer to Wiring Diagram Set 93, Reversing Lamps for schematic and connector information. Diagrams By Number
Normal Operation
The Smart Junction Box (SJB) provides voltage to the digital Transmission Range (TR) sensor (automatic transmission) or the reversing lamp switch (manual transmission) when the ignition is in RUN. When the transmission is placed in REVERSE, the digital TR sensor (or the reversing lamp switch) routes the voltage to the reversing lamps.
The reversing lamps share the ground circuit with the stoplamps.
This pinpoint test is intended to diagnose the following:
- Fuse
- Wiring, terminals or connectors
- Digital TR sensor (automatic transmission)
- Reversing lamp switch (manual transmission)
- SJB
PINPOINT TEST R: 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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R1 CHECK THE STOPLAMP OPERATION
- Ignition OFF.
- Apply and release the brake pedal while observing the stoplamps.
- Do the stoplamps operate correctly?
Yes
GO to R2.
No
REFER to Stoplamps Special Tool(s) Used With Diagnostics.
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R2 CHECK FOR VOLTAGE TO THE DIGITAL TR SENSOR OR THE REVERSING LAMP SWITCH
- Disconnect: Digital TR Sensor C167 (Automatic Transmission).
- Disconnect: Reversing Lamp Switch C169 (Manual Transmission).
- Ignition ON.
- Measure the voltage between the digital TR sensor C167-9, circuit CBP20 (YE/VT), harness side and ground; or between the reversing lamp switch C169-1, circuit CBP20 (YE/VT), harness side and ground.
- Is the voltage greater than 10 volts?
Yes
GO to R4.
No
VERIFY the SJB fuse 20 (10A) is OK. If OK, GO to R3. If not OK, REFER to the Wiring Diagrams to identify the possible causes of the circuit short. Diagrams By Number
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R3 CHECK THE VOLTAGE SUPPLY CIRCUIT FOR AN OPEN
- Ignition OFF.
- Disconnect: SJB C2280b.
- Measure the resistance between the digital TR sensor C167-9, circuit CBP20 (YE/VT), harness side and the SJB C2280b-23, circuit CBP20 (YE/VT), harness side; or between the reversing lamp switch C169-1, circuit CBP20 (YE/VT), harness side and the SJB C2280b-23, circuit CBP20 (YE/VT), harness side.
- Is the resistance less than 5 ohms?
Yes
GO to R5.
No
REPAIR circuit CBP20 (YE/VT) for an open. TEST the system for normal operation.
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R4 BYPASS THE DIGITAL TR SENSOR OR THE REVERSING LAMP SWITCH
- Ignition OFF.
- For vehicles with an automatic transmission, connect a fused jumper wire between the digital TR sensor C167-9, circuit CBP20 (YE/VT), harness side and the digital TR sensor C167-11, circuit CET41 (BN/YE), harness side.
- For vehicles with an automatic transmission, connect a fused jumper wire between the reversing lamp switch C169-1, circuit CBP20 (YE/VT), harness side and the reversing lamp switch C169-2, circuit CET41 (BN/YE), harness side.
- Ignition ON.
- Do the reversing lamps illuminate?
Yes
REMOVE the jumper wire.
For an automatic transmission, INSTALL a new digital TR sensor. REFER to Automatic Transmission - 5R44E and 5R55E Service and Repair. TEST the system for normal operation.
For a manual transmission, INSTALL a new reversing lamp switch. TEST the system for normal operation.
No
REMOVE the jumper wire. REPAIR circuit CET41 (BN/YE) for an open. TEST the system for normal operation.
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R5 CHECK FOR CORRECT SJB OPERATION
- Disconnect all the SJB connectors.
- Check for:
- corrosion
- damaged pins
- pushed-out pins
- Connect all the SJB 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 SJB. REFER to Multifunction Electronic Modules Service and Repair. 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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