Pinpoint Test G: One Or More Stoplamps Are Inoperative
Stoplamps
Pinpoint Tests
Pinpoint Test G: One Or More 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 Smart Junction Box (SJB) provides voltage to the stoplamp switch at all times. When the brake pedal is applied, voltage is routed to the high mounted stoplamp and the multifunction switch. The multifunction switch then routes the voltage to the LH and RH rear lamps. Both lamps share a common ground circuit.
This pinpoint test is intended to diagnose the following:
- Fuse
- Wiring, terminals or connectors
- Stoplamp switch
- High mounted stoplamp
- Multifunction switch
- SJB
PINPOINT TEST G: ONE OR MORE 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.
NOTE: Failure to disconnect the battery when instructed will result in false resistance readings. Refer to Battery, Mounting and Cables Battery Disconnect.
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G1 DETERMINE THE INOPERATIVE STOPLAMP
- Ignition OFF.
- Observe the stoplamps while applying the brake pedal.
- Are all the stoplamps inoperative?
Yes
GO to G2.
No
If the high mounted stoplamp is inoperative, GO to G5.
If both rear stoplamps are inoperative, GO to G7.
If one rear stoplamp is inoperative, GO to G9.
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G2 CHECK THE VOLTAGE TO THE STOPLAMP SWITCH
- Disconnect: Stoplamp Switch C278.
- Measure the voltage between the stoplamp switch C278-1, circuit SBP19 (BU/RD), harness side and ground.
- Is the voltage greater than 10 volts?
Yes
GO to G4.
No
VERIFY the SJB fuse 19 (20A) is OK. If OK, GO to G3. If not OK, REFER to the Wiring Diagrams to identify the possible causes of the circuit short. Diagrams By Number
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G3 CHECK THE STOPLAMP VOLTAGE SUPPLY CIRCUIT FOR AN OPEN
- Disconnect: SJB C2280b.
- Measure the resistance between the SJB C2280b-31, circuit SBP19 (BU/RD), harness side and the stoplamp switch C278-1, circuit SBP19 (BU/RD), harness side.
- Is the resistance less than 5 ohms?
Yes
GO to G11.
No
REPAIR circuit SBP19 (BU/RD) for an open. TEST the system for normal operation.
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G4 BYPASS THE STOPLAMP SWITCH
- Connect a fused jumper wire between the stoplamp switch C278-1, circuit SBP19 (BU/RD), harness side and the stoplamp switch C278-2, circuit CCB08 (VT/WH), harness side.
- Do the stoplamps illuminate?
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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G5 CHECK FOR VOLTAGE TO THE HIGH MOUNTED STOPLAMP
- Disconnect: High Mounted Stoplamp C904.
- While applying the brake pedal, measure the voltage between the high mounted stoplamp C904-2, circuit CCB08 (VT/WH), harness side and ground.
- Is the voltage greater than 10 volts?
Yes
GO to G6.
No
REPAIR the circuit. TEST the system for normal operation.
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G6 CHECK THE HIGH MOUNTED STOPLAMP GROUND CIRCUIT FOR AN OPEN
- Disconnect: Negative Battery Cable.
- Measure the resistance between the high mounted stoplamp C904-1, circuit GD161 (BK/YE), harness side and ground.
- Is the resistance less than 5 ohms?
Yes
INSTALL a new high mounted stoplamp. TEST the system for normal operation.
No
REPAIR circuit GD161 (BK/YE) for an open. TEST the system for normal operation.
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G7 CHECK FOR VOLTAGE TO THE MULTIFUNCTION SWITCH
- Disconnect: Multifunction Switch C202b.
- While applying the brake pedal, measure the voltage between the multifunction switch C202b-1, circuit CCB08 (VT/WH), harness side and ground.
- Is the voltage greater than 10 volts?
Yes
GO to G8.
No
REPAIR circuit CCB08 (VT/WH) for an open. TEST the system for normal operation.
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G8 CHECK THE REAR LAMP GROUND CIRCUIT FOR AN OPEN
- Disconnect: Negative Battery Cable.
- Disconnect: LH Rear Stoplamp C412.
- Measure the resistance between the LH rear lamp C412-1, circuit GD121 (BK/YE), harness side and ground.
- Is the resistance less than 5 ohms?
Yes
INSTALL a new multifunction switch. REFER to Steering Column Switches Steering Column Multifunction Switch. TEST the system for normal operation.
No
REPAIR circuit GD121 (BK/YE) for an open. TEST the system for normal operation.
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G9 CHECK FOR VOLTAGE TO THE REAR LAMP
- Disconnect: Inoperative Rear Stoplamp.
- While applying the brake pedal, measure the voltage between the LH rear lamp C412-3, circuit CLS35 (VT), harness side and ground; or between the RH rear lamp C415-3, circuit CLS36 (YE), harness side and ground.
- Is the voltage greater than 10 volts?
Yes
REPAIR circuit GD121 (BK/YE) for an open. TEST the system for normal operation.
No
GO to G10.
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G10 CHECK THE MULTIFUNCTION SWITCH
- Disconnect: Multifunction Switch.
- Carry out the multifunction switch component test.
Refer to Headlamp Dimmer Switch, Turn Signal Switch, Windshield Washer Switch, or Wiper Switch for component testing.
- Is the multifunction switch OK?
Yes
REPAIR circuit CLS35 (VT) (LH rear stoplamp) or circuit CLS36 (YE) (RH rear stoplamp) for an open. TEST the system for normal operation.
No
INSTALL a new multifunction switch. REFER to Steering Column Switches Steering Column Multifunction Switch. TEST the system for normal operation.
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G11 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. 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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