Pinpoint Test I: All The Stoplamps Are Inoperative

Stoplamps

Pinpoint Tests

Pinpoint Test I: 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

The stoplamp switch is supplied voltage from the Battery Junction Box (BJB) fuse 46 (10A). When the brake pedal is applied, the stoplamp switch routes voltage to the Body Control Module (BCM), indicating the brake pedal is applied.

The BCM provides voltage to all the stoplamps (on independent circuits) when it detects the brake pedal is applied.

This pinpoint test is intended to diagnose the following:

- Fuse
- Wiring, terminals or connectors
- Stoplamp switch
- BCM

PINPOINT TEST I: 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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I1 CHECK FOR VOLTAGE TO THE STOPLAMP SWITCH

- Ignition OFF.
- Disconnect: Stoplamp Switch C278.
- Measure the voltage between the stoplamp switch C278-4, circuit SBB46 (BN/RD), harness side and ground.




- Is the voltage greater than 10 volts?

Yes
GO to I2.

No
VERIFY the BJB fuse 46 (10A) is OK. If OK, REPAIR circuit SBB46 (BN/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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I2 BYPASS THE STOPLAMP SWITCH

- Connect a fused jumper wire between the stoplamp switch C278-4, circuit SBB46 (BN/RD), harness side and the stoplamp switch C278-1, 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
LEAVE the jumper wire connected. GO to I3.

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I3 CHECK THE STOPLAMP SWITCH SIGNAL TO THE BCM

- Disconnect: BCM C2280B.
- Measure the voltage between the BCM C2280B-28, circuit CCB08 (VT/WH), harness side and ground.




- Is the voltage greater than 10 volts?

Yes
REMOVE the jumper wire. GO to I4.

No
REMOVE the jumper wire. REPAIR circuit CCB08 (VT/WH) for an open. TEST the system for normal operation.

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I4 CHECK FOR CORRECT BCM OPERATION

- Disconnect all the BCM connectors.
- Check for:
- corrosion
- damaged pins
- pushed-out pins
- Connect all the BCM 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 BCM. 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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