Pinpoint Test I: One Or More Stoplamps Are Inoperative
Stoplamps
Pinpoint Tests
Pinpoint Test I: 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 - All Vehicles
When the brake pedal is applied, the stoplamp switch routes voltage to the Smart Junction Box (SJB). The voltage is then routed out of the SJB to the high mounted stoplamp through circuit CCB08 (VT/WH).
Explorer
When the SJB detects the brake pedal is applied, the SJB provides voltage to the LH and RH rear stoplamps through circuits CLS18 (GY/BN) and CLS19 (VT/OG). Ground for the high mounted stoplamp and the LH rear stoplamp is provided through circuit GD149 (BK/GY). Ground for the RH rear stoplamp is provided through circuit GD151 (BK/GN).
Explorer Sport Trac
When the SJB detects the brake pedal is applied, the SJB provides voltage to the LH and RH rear stoplamps through circuits CLS18 (GY/BN) and CLS19 (VT/OG). Ground for the high mounted stoplamp is provided through circuit GD133 (BK). Ground for the LH and RH rear stoplamps is provided through circuit GD148 (BK/YE).
Mountaineer
When the SJB detects the brake pedal is applied, the SJB provides voltage to the LH and RH rear stoplamps through circuit CLS44 (VT/BN). Ground for the high mounted stoplamp and the LH rear stoplamp is provided through circuit GD149 (BK/GY). Ground for the RH rear stoplamp is provided through circuit GD151 (BK/GN).
B2048-B2051 / C1788:
This pinpoint test is intended to diagnose the following:
- Fuse
- Wiring, terminals or connectors
- High mounted stoplamp
- LED module
- SJB
PINPOINT TEST I: 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.
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I1 CHECK THE RECORDED DTCs FROM THE SJB SELF-TEST
- Check the recorded results from the SJB self-test.
- Is DTC C1788, B2048 or B2050 recorded?
Yes
For DTC C1788, GO to I2.
For DTC B2048 or B2050, GO to I5.
No
GO to I7.
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I2 CHECK THE LH LED MODULE FOR A SHORT TO GROUND
- Disconnect: LH Rear Lamp C419.
- Ignition ON.
- Enter the following diagnostic mode on the scan tool: SJB Self-Test.
- Clear the DTCs and repeat the SJB on-demand self-test.
- Is DTC C1788 still present?
Yes
GO to I3.
No
INSTALL a new LED module. 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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I3 CHECK THE RH LED MODULE FOR A SHORT TO GROUND
- Disconnect: RH Rear Lamp C418.
- Enter the following diagnostic mode on the scan tool: SJB Self-Test.
- Clear the DTCs and repeat the SJB on-demand self-test.
- Is DTC C1788 still present?
Yes
GO to I4.
No
INSTALL a new LED module. 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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I4 CHECK CIRCUIT CLS44 (VT/BN) FOR A SHORT TO GROUND
- Ignition OFF.
- Disconnect: SJB C2280a.
- Measure the resistance between the LH rear lamp C419-1, circuit CLS44 (VT/BN), harness side and ground.
- Is the resistance greater than 10,000 ohms?
Yes
GO to I15.
No
VERIFY the SJB fuse 27 (15A) is OK. If OK, REPAIR the circuit. RUN the on-demand self-test (required to clear certain DTCs). CORRECT any unresolved DTCs. CLEAR all DTCs.
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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I5 CHECK THE BULB HOLDER FOR A SHORT TO GROUND
- Disconnect: Inoperative Stoplamp.
- Ignition ON.
- Enter the following diagnostic mode on the scan tool: SJB Self-Test.
- Clear the DTCs and repeat the SJB on-demand self-test.
- Is DTC B2048 or B2050 still present?
Yes
GO to I6.
No
INSTALL a new bulb holder in question. TEST the system for normal operation.
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I6 CHECK CIRCUIT CLS18 (GY/BN) OR CLS19 (VT/OG) FOR A SHORT TO GROUND
- Ignition OFF.
- Disconnect: SJB C2280a.
- For Explorer, measure the resistance between the inoperative rear lamp, harness side and ground as follows:
- For Explorer Sport Trac, measure the resistance between the inoperative rear lamp, harness side and ground as follows:
- Is the resistance greater than 10,000 ohms?
Yes
GO to I15.
No
VERIFY the SJB fuse 22 (15A) is OK. If OK, REPAIR the circuit 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. If not OK, REFER to the Wiring Diagrams to identify the possible causes of the circuit short.
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I7 DETERMINE THE INOPERATIVE STOPLAMP
- Ignition OFF.
- Apply the brake pedal.
- Verify the high mounted stoplamp operation.
- Is the high mounted stoplamp illuminated?
Yes
If one rear stoplamp is inoperative, GO to I11.
For Mountaineer, if both rear stoplamps are inoperative, GO to I13.
For Explorer Sport Trac, if both rear stoplamps are inoperative, GO to I14.
For Explorer, if both rear stoplamps are inoperative, GO to I15.
No
GO to I8.
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I8 CHECK CIRCUIT CCB08 (VT/WH) FOR VOLTAGE
- For Explorer or Mountaineer, while applying the brake pedal, measure the voltage between the high mounted stoplamp C475-1, circuit CCB08 (VT/WH), harness side and ground.
- For Explorer Sport Trac, while applying the brake pedal, measure the voltage between the high mounted stoplamp C927-3, circuit CCB08 (VT/WH), harness side and ground.
- Is the voltage greater than 10 volts?
Yes
GO to I9.
No
GO to I10.
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I9 CHECK THE HIGH MOUNTED STOPLAMP GROUND CIRCUIT FOR AN OPEN
- Disconnect: Negative Battery Cable.
- Disconnect: High Mounted Stoplamp C475 (Explorer, Mountaineer) or C927 (Explorer Sport Trac).
- For Explorer or Mountaineer, measure the resistance between the high mounted stoplamp C475-2, circuit GD149 (BK/GY), harness side and ground.
- For Explorer Sport Trac, measure the resistance between the high mounted stoplamp C927-1, circuit GD133 (BK), 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 the circuit. TEST the system for normal operation.
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I10 CHECK CIRCUIT CCB08 (VT/WH) FOR AN OPEN
- Disconnect: SJB C2280a.
- For Explorer or Mountaineer, measure the resistance between the high mounted stoplamp C475-1, circuit CCB08 (VT/WH), harness side and the SJB C2280a-15, circuit CCB08 (VT/WH), harness side.
- For Explorer Sport Trac, measure the resistance between the high mounted stoplamp C927-3, circuit CCB08 (VT/WH), harness side and the SJB C2280a-15, circuit CCB08 (VT/WH), harness side.
- Is the resistance less than 5 ohms?
Yes
GO to I15.
No
REPAIR the circuit. TEST the system for normal operation.
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I11 CHECK THE REAR LAMP GROUND CIRCUIT FOR AN OPEN
- Place the headlamp switch in the PARKING LAMPS ON position.
- Does the rear lamp in question illuminate?
Yes
For Mountaineer, TURN the parking lamps off. GO to I12.
For Explorer or Explorer Sport Trac, TURN the parking lamps off. GO to I13.
No
REPAIR the ground circuit in question for an open. CLEAR the DTCs. REPEAT the self-test.
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I12 CHECK CIRCUIT CLS44 (BU/RD) FOR AN OPEN
- Disconnect: Inoperative Rear Lamp.
- While applying the brake pedal, measure the voltage between the LH rear lamp (LED module) C419-1, circuit CLS44 (BU/RD), harness side and ground; or between the RH rear lamp (LED module) C418-1, circuit CLS44 (BU/RD), harness side and ground.
- Is the voltage greater than 10 volts?
Yes
INSTALL a new LED module. TEST the system for normal operation.
No
REPAIR the circuit. TEST the system for normal operation.
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I13 CHECK THE REAR STOPLAMP VOLTAGE SUPPLY CIRCUIT FOR AN OPEN
- Disconnect: Inoperative Rear Lamp.
- Disconnect: SJB C2280a.
- Measure the resistance between the inoperative rear lamp, harness side and the SJB, harness side as follows:
- Is the resistance less than 5 ohms?
Yes
GO to I15.
No
REPAIR the circuit in question. CLEAR the DTCs. REPEAT the self-test.
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I14 CHECK CIRCUIT GD148 (BK/YE) FOR AN OPEN
- Place the headlamp switch in the PARKING LAMPS ON position.
- Are both rear parking lamps inoperative?
Yes
REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.
No
GO to I15.
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I15 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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