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 - Taurus, Taurus X

The stoplamp switch is supplied voltage through circuit SBP02 (YE/RD) from the Smart Junction Box (SJB). When the brake pedal is applied, the stoplamp switch routes voltage to the SJB and the high mounted stoplamp through circuit CCB08 (VT/WH).

Sable

The stoplamp switch is supplied voltage through circuit SBP02 (YE/RD) from the SJB. When the brake pedal is applied, the stoplamp switch routes voltage to the rear lamps 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
- SJB



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 C278-2, circuit SBP02 (YE/RD), harness side and ground.




- Is the voltage greater than 10 volts?

Yes
GO to I2.

No
VERIFY the SJB fuse 2 (15A) is OK. If OK, GO to I3. If not OK, Refer to the Wiring Diagrams to identify the possible causes of the circuit short.

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I2 BYPASS THE STOPLAMP SWITCH


- Connect a fused jumper wire between the stoplamp switch C278-2, circuit SBP02 (YE/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
REMOVE the jumper wire. REPAIR circuit CCB08 (VT/WH) for an open. TEST the system for normal operation.

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I3 CHECK THE STOPLAMP SWITCH VOLTAGE SUPPLY CIRCUIT FOR AN OPEN


- Disconnect: SJB C2280d.
- Measure the resistance between the SJB C2280d-13, circuit SBP02 (YE/RD), harness side and the stoplamp switch C278-2, circuit SBP02 (YE/RD), harness side.




- Is the resistance less than 5 ohms?

Yes
GO to I4.

No
REPAIR circuit SBP02 (YE/RD) for an open. TEST the system for normal operation.

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I4 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.

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