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 through circuit SBB14 (BN/RD) from the Battery Junction Box (BJB). When the brake pedal is applied, the stoplamp switch routes voltage to the Smart Junction Box (SJB) and the high mounted stoplamp through circuit CCB08 (VT/WH).

This pinpoint test is intended to diagnose the following:

- Fuse
- Wiring, terminals or connectors
- Stoplamp switch



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 C278-1, circuit SBB14 (BN/RD), harness side and ground.




- Is the voltage greater than 10 volts?

Yes
GO to I2.

No
VERIFY the BJB fuse 14 (10A) is OK. If OK, REPAIR circuit SBB14 (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.

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I2 CHECK THE STOPLAMP SWITCH


- Connect a fused jumper wire between the stoplamp switch C278-1, circuit SBB14 (BN/RD), harness side and the stoplamp switch C278-2, circuit CCB08 (VT/WH), harness side.




- Are the stoplamps illuminated?

Yes
INSTALL a new stoplamp switch. REFER to Stoplamp Switch Service and Repair. TEST the system for normal operation.

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

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