Possible Sources
Visual Inspection and Diagnostic Pre-checks
Verify BJB fuse 20 (10A) is OK.
PINPOINT TEST A : ALL THE STOPLAMPS ARE INOPERATIVE
A1 CHECK THE STOPLAMP SWITCH VOLTAGE SUPPLY CIRCUIT FOR AN OPEN
Ignition OFF. Disconnect: Brake Pedal Position Switch C278. Measure:
Click to display connectors
Positive Lead | Measurement / Action | Negative Lead |
|---|---|---|
C278-1 | Ground |
Is the voltage greater than 11 volts?
Yes | GO to A2 |
|---|---|
No | VERIFY the BJB fuse 20 (10A) is OK. If OK, REPAIR the circuit. If not OK, REFER to the Wiring Diagram manual to identify the possible causes of the circuit short. After the repair: If no Diagnostic Trouble Codes (DTCs) are present, TEST the system for normal operation. If DTC U1000:00 is present, CLEAR the Diagnostic Trouble Codes (DTCs) and REPEAT the self-test (required to enable the lamp output driver if DTC U1000:00 is present). If DTC U3000:49 is present, Click here to access Guided Routine (BCM). |
A2 BYPASS THE STOPLAMP SWITCH
NOTE: If the fuse in the jumper wire fails, refer to the Wiring Diagrams manual to identify the possible causes of the circuit short.
Connect a fused jumper:
Click to display connectors
Positive Lead | Measurement / Action | Negative Lead |
|---|---|---|
C278-1 | C278-4 |
Ignition ON.
Do the stoplamps illuminate?
Yes | REMOVE the fused jumper wire. INSTALL a new brake pedal position (stoplamp) switch. REFER to: Stoplamp Switch (417-01 Exterior Lighting, Removal and Installation). |
|---|---|
No | LEAVE the fused jumper wire connected. GO to A3 |
2016 Mustang workshop publication supplied to Mustang Atlas. Original technical text and illustrations; HTML formatting by Mustang Atlas. Source page numbering is retained for traceability. Follow the configuration, revision, warnings, and cross-references in the material. About this edition.