Pinpoint Test J: One Or More Stoplamps Are Inoperative
Stoplamps
Pinpoint Tests
Pinpoint Test J: 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 stoplamp switch is supplied voltage through circuit SBB13 (GY/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 stoplamp relay (coil side) through circuit CCB08 (VT/WH). Ground for the stoplamp relay coil is provided through circuit GD122 (BK).
The SJB provides voltage to the rear stoplamps through circuits CLS18 (GY/BN) and CLS19 (VT/OG) when it receives input from the stoplamp switch indicating that the brake pedal is applied. Ground for the rear lamps is provided through circuit GD176 (BK/WH).
When the stoplamp relay is energized (brake pedal applied), voltage is routed from circuit SBB12 (GN/RD) to circuit CLS43 (YE/GN) to the high mounted stoplamp. Ground for the high mounted stoplamp is provided through circuit GD179 (BK/VT).
B2044-B2047:
This pinpoint test is intended to diagnose the following:
- Fuse
- Wiring, terminals or connectors
- High mounted stoplamp
- Bulb holder (vehicles with pickup bed)
- Rear lamp assembly (vehicles without pickup bed)
- Stoplamp relay
- SJB
PINPOINT TEST J: 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: Make sure the bulb is good before continuing diagnostics.
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J1 DETERMINE THE INOPERATIVE STOPLAMP
- Ignition OFF.
- Apply the brake pedal and observe the stoplamps.
- Are all the stoplamps inoperative?
Yes
Go To Pinpoint Test I. Pinpoint Test I: All The Stoplamps Are Inoperative
No
If the high mounted stoplamp is inoperative, GO to J2.
If both rear stoplamps are inoperative, GO to J8.
If an individual rear stoplamp is inoperative, GO to J10.
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J2 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 CLS43 (YE/GN), harness side and ground.
- Is the voltage greater than 10 volts?
Yes
GO to J3.
No
GO to J4.
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J3 CHECK FOR VOLTAGE TO THE HIGH MOUNTED STOPLAMP USING THE CONNECTOR GROUND
- While applying the brake pedal, measure the voltage between the high mounted stoplamp C904-2, circuit CLS43 (YE/GN), harness side and the high mounted stoplamp C904-1, circuit GD179 (BK/VT), harness side.
- Is the voltage greater than 10 volts?
Yes
INSTALL a new high mounted stoplamp. TEST the system for normal operation.
No
REPAIR circuit GD179 (BK/VT) for an open. TEST the system for normal operation.
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J4 CHECK THE STOPLAMP RELAY
- Connect: High Mounted Stoplamp C904.
- Disconnect: Stoplamp Relay.
- Substitute a known good relay and check the operation of the high mounted stoplamp.
- Does the high mounted stoplamp operate correctly?
Yes
REMOVE the known good relay. INSTALL a new stoplamp relay. TEST the system for normal operation.
No
REMOVE the known good relay. GO to J5.
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J5 CHECK THE STOPLAMP SWITCH OUTPUT CIRCUIT FOR AN OPEN (TO THE STOPLAMP RELAY)
- While applying the brake pedal, measure the voltage between the stoplamp relay pin 1, circuit CCB08 (VT/WH), BJB face side and ground.
- Is the voltage greater than 10 volts?
Yes
GO to J6.
No
REPAIR circuit CCB08 (VT/WH) for an open. TEST the system for normal operation.
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J6 CHECK THE STOPLAMP SWITCH OUTPUT CIRCUIT FOR VOLTAGE USING THE RELAY GROUND PIN
- While applying the brake pedal, measure the voltage between the stoplamp relay pin 1, circuit CCB08 (VT/WH), BJB face side and the stoplamp relay pin 2, circuit GD122 (BK), BJB face side.
- Is the voltage greater than 10 volts?
Yes
GO to J7.
No
REPAIR circuit GD122 (BK) for an open. TEST the system for normal operation.
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J7 CHECK THE STOPLAMP RELAY VOLTAGE SUPPLY CIRCUIT FOR AN OPEN
- Measure the voltage between the stoplamp relay pin 3, circuit SBB12 (GN/RD), BJB face side and ground.
- Is the voltage greater than 10 volts?
Yes
REPAIR circuit CLS43 (YE/GN) for an open. TEST the system for normal operation.
No
VERIFY the BJB fuse 12 (15A) is OK. If OK, REPAIR circuit SBB12 (GN/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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J8 CHECK THE STOPLAMP SWITCH OUTPUT CIRCUIT FOR AN OPEN (TO THE SJB)
- Disconnect: SJB C2280b.
- While applying the brake pedal, measure the voltage between the SJB C2280b-40, circuit CCB08 (VT/WH), harness side and ground.
- Is the voltage greater than 10 volts?
Yes
VERIFY the SJB fuse 6 (20A) is OK. If OK, GO to J9. If not OK, REFER to the Wiring Diagrams to identify the possible causes of the circuit short.
No
REPAIR circuit CCB08 (VT/WH) for an open. CLEAR the DTCs. REPEAT the self-test.
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J9 CHECK FOR VOLTAGE TO THE LH REAR LAMP ASSEMBLY
- Disconnect: LH Rear Lamp C4035 or C423.
- For vehicles with a pickup bed, while applying the brake pedal, measure the voltage between the LH rear lamp C4035-3, circuit CLS18 (GY/BN), harness side and the ground.
- For vehicles without a pickup bed (chassis cab vehicles), while applying the brake pedal, measure the voltage between the LH rear lamp C423-4, circuit CLS18 (GY/BN), harness side and the ground.
- Is the voltage greater than 10 volts?
Yes
REPAIR circuit GD176 (BK/WH) for an open. CLEAR the DTCs. REPEAT the self-test.
No
GO to J16.
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J10 USE THE RECORDED DTCs FROM THE SJB SELF-TEST
- Check the recorded results from the SJB on-demand self-test.
- Was DTC B2045 or DTC B2047 present?
Yes
GO to J11.
No
GO to J14.
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J11 CHECK FOR VOLTAGE TO THE BULB HOLDER/LAMP ASSEMBLY
- Disconnect: Inoperative Rear Lamp.
- For vehicles with a pickup bed, while applying the brake pedal, measure the voltage between the LH rear lamp C4035-3, circuit CLS18 (GY/BN), harness side and the ground; or between the RH rear lamp C4032-3, circuit CLS19 (VT/OG), harness side and ground.
- For vehicles without a pickup bed (chassis cab vehicles), while applying the brake pedal, measure the voltage between the LH rear lamp C423-4, circuit CLS18 (GY/BN), harness side and the ground; or between the RH rear lamp C422-4, circuit CLS19 (VT/OG), harness side and ground.
- Is the voltage greater than 10 volts?
Yes
GO to J12.
No
GO to J13.
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J12 CHECK FOR VOLTAGE TO THE BULB HOLDER/LAMP ASSEMBLY USING THE CONNECTOR GROUND
- For vehicles with a pickup bed, while applying the brake pedal, measure the voltage between the LH rear lamp C4035-3, circuit CLS18 (GY/BN), harness side and the LH rear lamp C4035-1, circuit GD176 (BK/WH), harness side; or between the RH rear lamp C4032-3, circuit CLS19 (VT/OG), harness side and the RH rear lamp C4032-1, circuit GD176 (BK/WH), harness side.
- For vehicles without a pickup bed (chassis cab vehicles), while applying the brake pedal, measure the voltage between the LH rear lamp C423-4, circuit CLS18 (GY/BN), harness side and the LH rear lamp C423-2, circuit GD176 (BK/WH), harness side; or between the RH rear lamp C422-4, circuit CLS19 (VT/OG), harness side and the RH rear lamp C422-2, circuit GD176 (BK/WH), harness side.
- Is the voltage greater than 10 volts?
Yes
INSTALL a new bulb holder (vehicles with a pickup bed) or a new rear lamp assembly (chassis cab vehicles). CLEAR the DTCs. REPEAT the self-test.
No
REPAIR circuit GD176 (BK/WH) for an open. CLEAR the DTCs. REPEAT the self-test.
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J13 CHECK THE REAR STOPLAMP VOLTAGE SUPPLY CIRCUIT FOR AN OPEN
- Disconnect: SJB C2280d.
- For vehicles with a pickup bed, measure the resistance between the LH rear lamp C4035-3, circuit CLS18 (GY/BN), harness side and the SJB C2280d-25, circuit CLS18 (GY/BN), harness side; or between the RH rear lamp C4032-3, circuit CLS19 (VT/OG), harness side and the SJB C2280d-26, circuit CLS19 (VT/OG), harness side.
- For vehicles without a pickup bed (chassis cab vehicles), measure the resistance between the LH rear lamp C423-4, circuit CLS18 (GY/BN), harness side and the SJB C2280d-25, circuit CLS18 (GY/BN), harness side; or between the RH rear lamp C422-4, circuit CLS19 (VT/OG), harness side and the SJB C2280d-26, circuit CLS19 (VT/OG), harness side.
- Is the resistance less than 5 ohms?
Yes
GO to J16.
No
REPAIR the circuit in question for an open. CLEAR the DTCs. REPEAT the self-test.
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J14 CHECK THE BULB HOLDER FOR THE CAUSE OF THE SHORT TO GROUND
- Disconnect: Inoperative Rear Lamp.
- Repeat the SJB on-demand self-test.
- For vehicles with a pickup bed, while applying the brake pedal, measure the voltage between the LH rear lamp C4035-3, circuit CLS18 (GY/BN), harness side and the ground; or between the RH rear lamp C4032-3, circuit CLS19 (VT/OG), harness side and ground.
- For vehicles without a pickup bed (chassis cab vehicles), while applying the brake pedal, measure the voltage between the LH rear lamp C423-4, circuit CLS18 (GY/BN), harness side and the ground; or between the RH rear lamp C422-4, circuit CLS19 (VT/OG), harness side and ground.
- Is the voltage greater than 10 volts?
Yes
INSTALL a new bulb holder in question. RUN the on-demand self-test (required to clear certain DTCs). CORRECT any unresolved DTCs. CLEAR all DTCs. TEST the system for normal operation.
No
GO to J15.
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J15 CHECK THE REAR STOPLAMP VOLTAGE SUPPLY CIRCUIT FOR A SHORT TO GROUND
- Ignition OFF.
- Disconnect: SJB C2280d.
- Measure the resistance between the SJB C2280d-25 (LH stoplamp), circuit CLS18 (GY/BN), harness side and ground; or between the SJB C2280d-26 (RH stoplamp), circuit CLS19 (VT/OG), harness side and ground.
- Is the resistance greater than 10,000 ohms?
Yes
GO to J16.
No
REPAIR the circuit in question for a short to ground. RUN the on-demand self-test (required to clear certain DTCs). CORRECT any unresolved DTCs. CLEAR all DTCs. TEST the system for normal operation.
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J16 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. CLEAR the DTCs. REPEAT the self-test.
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