Pinpoint Test K: The Stoplamp(s) Are On Continuously
Stoplamps
Pinpoint Test K: The Stoplamp(s) Are On Continuously
Normal Operation
When the brake pedal is applied, the stoplamp switch routes voltage to the PCM and to the Body Control Module (BCM) to indicate that the brake pedal is applied.
The BCM (Body Control Module) provides voltage to all the stoplamps (on independent circuits) when it detects that the brake pedal is applied.
The voltage from the stoplamp switch also passes through the BCM (Body Control Module) fuse 31 (5A) and is routed to the Trailer Brake Control (TBC) module on one circuit and for a customer access use on another circuit.
This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- Stoplamp switch
- TBC (Trailer Brake Control) module
- PCM
- BCM (Body Control Module)
PINPOINT TEST K : THE STOPLAMP(S) ARE ON CONTINUOUSLY
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 (Body Control Module) 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 (Trailer Brake Control) module, GO to K5.
If the vehicle is not equipped with an aftermarket TBC (Trailer Brake Control) module, GO to K6.
No
GO to K8.
K5 CHECK THE TBC (Trailer Brake Control) MODULE
- Ignition OFF.
- Disconnect: TBC (Trailer Brake Control) Module C2142.
- Ignition ON.
Do the stoplamps continue to illuminate?
Yes
GO to K6.
No
INSTALL a new TBC (Trailer Brake Control) module. TEST the system for normal operation.
K6 CHECK THE CUSTOMER ACCESS CIRCUIT FOR A SHORT TO VOLTAGE
- Ignition OFF.
- Disconnect: BCM (Body Control Module) 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 (Trailer Brake Control) MODULE BRAKE INPUT CIRCUIT FOR A SHORT TO VOLTAGE
- Ignition OFF.
- Disconnect: BCM (Body Control Module) C2280B.
- Ignition ON.
- Measure the voltage between the BCM (Body Control Module) C2280B-28, circuit CCB08 (VT/WH), harness side and ground; and between the BCM (Body Control Module) C2280B-4, circuit CBP31 (BU/OG), harness side and ground
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. 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 (Body Control Module) OPERATION
- Disconnect all the BCM (Body Control Module) connectors.
- Check for:
- corrosion
- damaged pins
- pushed-out pins
- Connect all the BCM (Body Control Module) 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 (Body Control Module). 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.