Pinpoint Test K: The STOPLAMP(S) Are On Continuously

WARNING: This page is about a different car, the 2014 Ford F-150. However, it is still accessible from the selected car via links, so may be relevant.

K1 DETERMINE IF ALL THE STOPLAMPS ARE ON
- Ignition ON.
- Observe the stoplamps.
Are all the stoplamps on?
- Yes : GO to K3.
- No : GO to K2 .
K2 CHECK THE STOPLAMP VOLTAGE SUPPLY CIRCUITS FOR A SHORT TO VOLTAGE
- Ignition OFF.
- Disconnect: BCM C2280D .
- Ignition ON.
Does any stoplamp continue to illuminate?
- Yes : If the LH rear lamps continue to illuminate, REPAIR circuit CLS18 (GY/BN) for a short to voltage. TEST the system for normal operation.
  If the RH rear lamps continue to illuminate, REPAIR circuit CLS19 (VT/OG) for a short to voltage. TEST the system for normal operation.
  
  If the high mounted stoplamp continues to illuminate, REPAIR circuit CLS52 (BN) for a short to voltage. TEST the system for normal operation.
- No : GO to K9.
K3 CHECK THE STOPLAMP SWITCH
- Disconnect: Stoplamp Switch C278 .
Do the stoplamps continue to illuminate?
- Yes : GO to K4 .
- No : INSTALL a new stoplamp switch. REFER to STOPLAMP SWITCH . TEST the system for normal operation.
K4 CHECK THE PCM
- Ignition OFF.
- Disconnect: PCM C1551 (3.5L), C175B (3.7L) or C1381B (5.0L/6.2L).
- Ignition ON.
Do the stoplamps continue to illuminate?
- Yes : If the vehicle is equipped with an aftermarket TBC module, GO to K5 .
  If the vehicle is not equipped with an aftermarket TBC module, GO to K6.
- No : GO to K8.
K5 CHECK THE TBC MODULE
- Ignition OFF.
- Disconnect: TBC Module C2142 .
- Ignition ON.
Do the stoplamps continue to illuminate?
- Yes : GO to K6 .
- No : INSTALL a new TBC module. TEST the system for normal operation.
K6 CHECK THE CUSTOMER ACCESS CIRCUIT FOR A SHORT TO VOLTAGE
- Ignition OFF.
- Disconnect: BCM C2280F .
- Ignition ON.
Do the stoplamps continue to illuminate?
- Yes : GO to K7 .
- No : REPAIR circuit CBP31 (BU/OG) for a short to voltage. TEST the system for normal operation.
K7 CHECK THE STOPLAMP SWITCH INPUT AND TBC MODULE BRAKE INPUT CIRCUIT FOR A SHORT TO VOLTAGE
- Ignition OFF.
- Disconnect: BCM C2280B .
- Ignition ON.
- Measure the voltage between the BCM C2280B-28 , circuit CCB08 (VT/WH), harness side and ground; and between the BCM C2280B-4 , circuit CBP31 (BU/OG), harness side and ground
  
  Fig 1: Measuring Voltage Between BCM C2280B-28, Circuit CCB08 (VT/WH) And Ground
  Courtesy of FORD MOTOR CO.
Is any voltage present?
- Yes : REPAIR circuit CCB08 (VT/WH) or circuit CBP31 (BU/OG) for a short to voltage as necessary. TEST the system for normal operation.
- No : GO to K9.
K8 CHECK FOR CORRECT PCM OPERATION
- Disconnect all the PCM connectors.
- Check for:
  - corrosion
  - damaged pins
  - pushed-out pins
- Connect all the PCM 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 PCM. REFER to ELECTRONIC ENGINE CONTROLS . 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.
K9 CHECK FOR CORRECT BCM OPERATION
- Disconnect all the BCM connectors.
- Check for:
  - corrosion
  - damaged pins
  - pushed-out pins
- Connect all the BCM 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 BCM . REFER to MULTIFUNCTION ELECTRONIC MODULES . 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.