Pinpoint Test J: The STOPLAMPS Are Inoperative

WARNING: This page is about a different car, the 2006 Mercury Mariner and 2006 Ford Escape. However, it is still accessible from the selected car via links, so may be relevant.

J1 CHECK CIRCUIT 10 (LG/RD) FOR VOLTAGE
- Key in OFF position.
- Disconnect: Stoplamp Switch C278.
- Measure the voltage between the stoplamp switch C278-2, circuit 10 (LG/RD), harness side and ground.
  
  Fig 1: Checking Circuit 10 (LG/RD) For Voltage
  Courtesy of FORD MOTOR CO.
- Is the voltage greater than 10 volts?
Yes: GO to J2.

No: VERIFY the SJB fuse 6 (15A) is OK. If OK, GO to J3.
J2 CHECK THE STOPLAMP SWITCH
- Connect a fused (15A) jumper wire between the stoplamp switch C278-2, circuit 10 (LG/RD), harness side and the stoplamp switch C278-1, circuit 511 (LG), harness side.
  
  Fig 2: Checking Stoplamp Switch
  Courtesy of FORD MOTOR CO.
- Are the stoplamps illuminated?
Yes: INSTALL a new stoplamp switch. REFER to STOPLAMP SWITCH . TEST the system for normal operation.

No: REPAIR circuit 511 (LG). CLEAR the DTCs. REPEAT the self-test.
J3 CHECK CIRCUIT 10 (RD/LG) FOR AN OPEN
- Disconnect: SJB C2280c.
- Measure the resistance between the SJB C2280c-17, circuit 10 (LG/RD), harness side and the stoplamp switch C278-2, circuit 10 (LG/RD), harness side.
  
  Fig 3: Checking Circuit 10 (RD/LG) For An Open
  Courtesy of FORD MOTOR CO.
- Is the resistance less than 5 ohms?
Yes: GO to J4.

No: REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.
J4 CHECK FOR CORRECT SJB OPERATION
- Disconnect all the SJB connectors.
- Check for:
  - corrosion
  - 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 SMART JUNCTION BOX (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.