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). When the brake pedal is applied, the stoplamp switch routes voltage to the Smart Junction Box (SJB) and the stoplamp relay (coil side).

The SJB provides voltage to the rear lamps when it receives input from the stoplamp switch indicating that the brake pedal is applied.

When the stoplamp relay is energized (brake pedal applied), voltage is routed to the high mounted stoplamp.

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 THE BRAKE PEDAL SWITCH VOLTAGE SUPPLY CIRCUIT FOR AN OPEN


- Ignition OFF.
- Disconnect: Stoplamp Switch C278.
- Measure the voltage between the stoplamp switch C278-1, circuit SBB13 (GY/RD), harness side and ground.




- Is the voltage greater than 10 volts?

Yes
GO to I2.

No
VERIFY the BJB fuse 13 (5A) is OK. If OK, REPAIR circuit SBB13 (GY/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 CHECK THE STOPLAMP SWITCH


- Connect a fused jumper wire between the stoplamp switch C278-1, circuit SBB13 (GY/RD), harness side and the stoplamp switch C278-2, 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
REMOVE the jumper wire. REPAIR circuit CCB08 (VT/WH) for an open. TEST the system for normal operation.

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