Pinpoint Test I: The STOPLAMPS Are Inoperative

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

I1 CHECK THE STOPLAMP SWITCH INPUT
- Key in ON position.
- Enter the following diagnostic mode on the scan tool: SJB Stoplamp Switch PID.
- Monitor the SJB stoplamp switch PID while applying the brake pedal.
- Does the PID indicate active with the brake pedal applied?
Yes: For Freestyle and Five Hundred, GO to I6.

For Montego, GO to I5.

No: GO to I2.
I2 CHECK CIRCUIT 1140 (VT) FOR VOLTAGE
- Key in OFF position.
- Disconnect: Stoplamp Switch C278.
- Measure the voltage between the stoplamp switch C278-2, circuit 1140 (VT), harness side and ground.
  
  Fig 1: Measuring Voltage Between Stoplamp Switch C278-2, Circuit 1140 (VT), Harness Side & Ground
  Courtesy of FORD MOTOR CO.
- Is the voltage greater than 10 volts?
Yes: GO to I3.

No: VERIFY the SJB fuse 18 (10A) is OK. If OK, REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.
I3 CHECK THE STOPLAMP SWITCH
- Connect a fused jumper wire between the stoplamp switch C278-2, circuit 1140 (VT), harness side and the stoplamp switch C278-1, circuit 810 (RD/LG), harness side.
  
  Fig 2: Checking Stoplamp Switch
  Courtesy of FORD MOTOR CO.
- Do the stoplamps illuminate?
Yes: INSTALL a new stoplamp switch. REFER to STOPLAMP SWITCH . CLEAR the DTCs. REPEAT the self-test.

No: REMOVE the jumper wire. GO to I4.
I4 CHECK CIRCUIT 810 (RD/LG) FOR AN OPEN
- Disconnect: SJB C2280a.
- Measure the resistance between the SJB C2280a-8, circuit 810 (RD/LG), harness side and the stoplamp switch C278-1, circuit 810 (RD/LG), harness side.
  
  Fig 3: Checking Circuit 810 (RD/LG)
  Courtesy of FORD MOTOR CO.
- Is the resistance less than 5 ohms?
Yes: GO to I6.

No: REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.
I5 CHECK CIRCUIT 1374 (TN/LB) FOR AN OPEN
- Key in OFF position.
- Disconnect: SJB C2280e.
- Disconnect: LH Rear Lamp Assembly C414.
- Measure the resistance between the LH rear lamp assembly C414-3, circuit 1374 (TN/LB), harness side and the SJB C2280e-9, circuit 1374 (TN/LB), harness side.
  
  Fig 4: Checking Circuit 1374 (TN/LB)
  Courtesy of FORD MOTOR CO.
- Is the resistance less than 5 ohms?
Yes: GO to I6.

No: REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.
I6 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 REMOVAL AND INSTALLATION . 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.