Pinpoint Test G: All The Stoplamps Are Inoperative
Stoplamps
Pinpoint Tests
Pinpoint Test G: All The Stoplamps Are Inoperative
Refer to Wiring Diagram Set 90, Turn Signal/Stop/Hazard Lamps for schematic and connector information. Diagrams By Number
Normal Operation - Wagon
The stoplamp switch is supplied voltage through circuit SBB30 (WH/RD) from the Battery Junction Box (BJB). When the brake pedal is applied, the stoplamp switch routes voltage back to the Smart Junction Box (SJB) and the high mounted stoplamp through circuit CCB08 (VT/WH). The SJB provides voltage to the LH and RH rear stoplamps when it receives input from the stoplamp switch indicating that the brake pedal is applied. Ground is shared by all the stoplamps through circuit GD149 (BK/GY).
Cutaway Chassis
The stoplamp switch is supplied voltage through circuit SBB30 (WH/RD) from the BJB. When the brake pedal is applied, the stoplamp switch routes voltage back to the SJB and the body builder connector through circuit CCB08 (VT/WH). The SJB provides voltage to the LH and RH rear stoplamps to the body builder connector when it receives input from the stoplamp switch indicating that the brake pedal is applied. Ground for the stoplamps is provided by the body builder.
Stripped Chassis
The stoplamp switch is supplied voltage through circuit SBB30 (WH/RD) from the BJB. When the brake pedal is applied, the stoplamp switch routes voltage to the SJB and the body builder connector through circuit CCB08 (VT/WH). The SJB provides voltage to the LH and RH rear stoplamps to the body builder connector when it receives input from the stoplamp switch indicating that the brake pedal is applied. Ground for the stoplamps is provided by the body builder.
This pinpoint test is intended to diagnose the following:
- Fuse
- Wiring, terminals or connectors
- Stoplamp switch
- Body builder equipment
- SJB
PINPOINT TEST G: ALL THE STOPLAMPS 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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G1 MONITOR THE STOPLAMP SWITCH INPUT
- Ignition ON.
- Enter the following diagnostic mode on the scan tool: SJB DataLogger.
- Monitor the SJB stoplamp switch PID (GEM_BOO) while applying the brake pedal.
- Does the PID indicate the brake pedal is applied?
Yes
For wagon, REPAIR circuit GD149 (BK/GY) for an open. TEST the system for normal operation.
For cutaway or stripped chassis vehicles, VERIFY the BJB fuse 30 (10A) is OK. If OK, the vehicle is operating correctly. REFER to the body builder information to continue diagnosis.
If not OK, REFER to the Wiring Diagrams to identify the possible causes of the circuit short. After the repair:
If no DTCs are present, TEST the system for normal operation.
If DTC B106E is present, CLEAR the DTCs and REPEAT the self-test (required to enable the backlighting output driver if DTC B106E is present). TEST the system for normal operation.
If DTC B106F is present, INSTALL a new SJB. TEST the system for normal operation.
No
GO to G2.
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G2 CHECK FOR VOLTAGE TO THE STOPLAMP SWITCH
- Ignition OFF.
- Disconnect: Stoplamp Switch C278.
- Measure the voltage between the stoplamp switch C278-1, circuit SBB30 (WH/RD), harness side and ground.
- Is the voltage greater than 10 volts?
Yes
GO to G3.
No
VERIFY the BJB fuse 30 (10A) is OK. If OK, REPAIR circuit SBB30 (WH/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.
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G3 BYPASS THE STOPLAMP SWITCH
- Connect a fused jumper wire between the stoplamp switch C278-1, circuit SBB30 (WH/RD), harness side and the stoplamp switch C278-4, circuit CCB08 (VT/WH), harness side.
- Are the stoplamps illuminated?
Yes
REMOVE the jumper wire. INSTALL a new stoplamp switch. REFER to Stoplamp Switch Service and Repair. TEST the system for normal operation.
No
For wagon, REMOVE the jumper wire. REPAIR circuit CCB08 (VT/WH) for an open. TEST the system for normal operation.
For cutaway or stripped chassis vehicles, LEAVE the jumper wire connected. GO to G4.
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G4 CHECK THE STOPLAMP SWITCH INPUT TO THE SJB
- Disconnect: SJB C2280b.
- Measure the voltage between the SJB C2280b-40, circuit CCB08 (VT/WH), harness side and ground.
- Is the voltage greater than 10 volts?
Yes
GO to G5.
No
REPAIR circuit CCB08 (VT/WH) for an open. TEST the system for normal operation.
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G5 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. 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 the DTCs. REPEAT the self-test.
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