Pinpoint Test O: One Or More Parking, Rear or License Plate Lamps Is Inoperative
Parking, Rear and License Plate Lamps
Pinpoint Test O: One Or More Parking, Rear or License Plate Lamps Is Inoperative
Normal Operation
The Steering Column Control Module (SCCM) sends voltage signals to the headlamp switch through the headlamp switch input circuits (off, parking lamps, headlamps, autolamps). At any given time, the headlamp switch routes one of the input circuits to ground, indicating the headlamp switch position to the SCCM (Steering Column Control Module).
The SCCM (Steering Column Control Module) sends the status of the headlamp switch position to the Body Control Module (BCM) over the High Speed Controller Area Network (HS-CAN).
The BCM (Body Control Module) provides voltage to the parking lamps based on the headlamp switch position.
If the SCCM (Steering Column Control Module) detects multiple or no active headlamp switch inputs, the SCCM (Steering Column Control Module) sends a message to the BCM (Body Control Module) to indicate a fault with the headlamp switch input.
If the BCM (Body Control Module) receives a message from the SCCM (Steering Column Control Module) indicating a fault with the headlamp switch inputs or the BCM (Body Control Module) loses communication with the SCCM (Steering Column Control Module), the BCM (Body Control Module) defaults the exterior lamps on.
This pinpoint test is intended to diagnose the following:
- Fuse
- Wiring, terminals or connectors
- Bulb holder
- Rear lamp assembly (vehicles without pickup bed)
- Cab marker lamp
- Exterior mirror
- BCM (Body Control Module)
PINPOINT TEST O : ONE OR MORE PARKING, REAR OR LICENSE PLATE LAMPS IS INOPERATIVE
NOTICE: Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may damage the connector.
O1 DETERMINE IF ALL THE PARKING LAMPS ARE INOPERATIVE
- Ignition OFF.
- Place the headlamp switch in the PARKING LAMPS ON position.
Are all the parking lamps inoperative?
Yes
If the vehicle is equipped with cab marker lamps, GO to O7.
If the vehicle is not equipped with cab marker lamps, VERIFY the BCM (Body Control Module) fuse 30 (15A) is OK. If OK, GO to O4. If not OK, REFER to the Wiring Diagrams to identify the possible causes of the circuit short. [1][2]Diagrams By Number
No
If all the cab marker lamps are inoperative, VERIFY the BCM (Body Control Module) fuse 40 (10A) is OK. If OK, GO to O2. If not OK, REFER to the Wiring Diagrams to identify the possible causes of the circuit short.
If all the front and rear parking lamps are inoperative, VERIFY the BCM (Body Control Module) fuse 30 (15A) is OK. If OK, GO to O4. If not OK, REFER to the Wiring Diagrams to identify the possible causes of the circuit short. [1][2]Diagrams By Number
For any other inoperative lamp, GO to O5.
O2 BYPASS THE BCM (Body Control Module) (CAB MARKER LAMPS)
NOTE: If the fuse in the jumper wire fails, refer to the Wiring Diagrams to identify the possible causes of the circuit short. [1][2]Diagrams By Number
- Place the headlamp switch in the OFF position.
- Disconnect: BCM (Body Control Module) C2280D.
- Connect a fused jumper wire between the positive battery terminal and the BCM (Body Control Module) C2280D-18, circuit CBP40 (YE/GN), harness side.
Do the cab marker lamps illuminate?
Yes
REMOVE the jumper wire. GO to O7.
No
LEAVE the jumper wire connected. GO to O3.
O3 CHECK THE PARKING LAMP SUPPLY VOLTAGE CIRCUIT FOR AN OPEN (CAB MARKER LAMPS)
- Disconnect: Any Cab Marker Lamp.
- Measure the voltage between an inoperative cab marker lamp, harness side and ground as follows:
Inoperative Lamp Connector-Pin Circuit LH outer cab marker C970-1 CBP40 or CLS30 (YE/GN or VT/WH) LH inner cab marker C971-1 CBP40 or CLS30 (YE/GN or VT/WH) Center cab marker C972-1 CBP40 or CLS30 (YE/GN or VT/WH) RH inner cab marker C973-1 CBP40 or CLS30 (YE/GN or VT/WH) RH outer cab marker C974-1 CBP40 or CLS30 (YE/GN or VT/WH)
Is the voltage greater than 10 volts?
Yes
REMOVE the jumper wire. REPAIR circuit GD137 (BK/WH) for an open. TEST the system for normal operation.
No
REMOVE the jumper wire. REPAIR circuit CBP40 or CLS30 (YE/GN or VT/WH) for an open. TEST the system for normal operation.
O4 BYPASS THE BCM (Body Control Module) (FRONT AND REAR LAMPS)
NOTE: If the fuse in the jumper wire fails, refer to the Wiring Diagrams to identify the possible causes of the circuit short. [1][2]Diagrams By Number
- Place the headlamp switch to the OFF position.
- Disconnect: BCM (Body Control Module) C2280E.
- Connect a fused jumper wire between the positive battery terminal and the BCM (Body Control Module) C2280E-6, circuit CBP30 (YE/BU), harness side.
Do the front, rear and license plate lamps illuminate?
Yes
REMOVE the jumper wire. GO to O7.
No
REMOVE the jumper wire. REPAIR circuit CBP30 (YE/BU) for an open. TEST the system for normal operation.
O5 CHECK FOR VOLTAGE TO THE INOPERATIVE PARKING LAMP
- Place the headlamp switch in the OFF position.
- Disconnect: Inoperative Lamp.
- Place the headlamp switch in the PARKING LAMPS ON position.
- Measure the voltage between the inoperative lamp, harness side and ground as follows:
Inoperative Lamp Connector-Pin Circuit LH front C1023-2 CBP30 (YE/BU) RH front C1043-2 CBP30 (YE/BU) LH front side marker C1127-1 CBP30 (YE/BU) RH front side marker C1126-1 CBP30 (YE/BU) LH outer cab marker C970-1 CBP40 or CLS30 (YE/GN or VT/WH) LH inner cab marker C971-1 CBP40 or CLS30 (YE/GN or VT/WH) Center cab marker C972-1 CBP40 or CLS30 (YE/GN or VT/WH) RH inner cab marker C973-1 CBP40 or CLS30 (YE/GN or VT/WH) RH outer cab marker C974-1 CBP40 or CLS30 (YE/GN or VT/WH) LH exterior mirror C521-5 CBP40 (YE/GN) RH exterior mirror C601-5 CBP40 (YE/GN) LH rear (with pickup bed) C4035-2 CBP30 (YE/BU) RH rear (with pickup bed) C4032-2 CBP30 (YE/BU) LH rear (without pickup bed) C423-3 CBP30 (YE/BU) RH rear (without pickup bed) C422-3 CBP30 (YE/BU) Center rear lamp assembly (below tailgate) C4001-3 CBP30 (YE/BU) LH rear side marker 1 C4094-1 CBP30 (YE/BU) LH rear side marker 2 C4095-1 CBP30 (YE/BU) RH rear side marker 1 C4096-1 CBP30 (YE/BU) RH rear side marker 2 C4097-1 CBP30 (YE/BU) LH license plate C452-1 CBP30 (YE/BU) RH license plate C462-1 CBP30 (YE/BU)
Is the voltage greater than 10 volts?
Yes
For the license plate lamps, REPAIR circuit GD176 (BK/WH) for an open. TEST the system for normal operation.
For all others, GO to O6.
No
REPAIR the parking lamp voltage supply circuit in question for an open. TEST the system for normal operation.
O6 CHECK THE INOPERATIVE PARKING LAMP GROUND CIRCUIT FOR AN OPEN
- Measure the voltage between the inoperative lamp, harness side as follows:
Inoperative Lamp Connector-Pin Circuit Connector-Pin Circuit LH front C1023-2 CBP30 (YE/BU) C1023-1 GD122 (BK) RH front C1043-2 CBP30 (YE/BU) C1043-1 GD124 (BK/VT) LH front side marker C1127-1 CBP30 (YE/BU) C1127-2 GD122 (BK) RH front side marker C1126-1 CBP30 (YE/BU) C1126-2 GD124 (BK/VT) LH outer cab marker C970-1 CBP40 or CLS30 (YE/GN or VT/WH) C970-3 GD137 (BK/WH) LH inner cab marker C971-1 CBP40 or CLS30 (YE/GN or VT/WH) C971-3 GD137 (BK/WH) Center cab marker C972-1 CBP40 or CLS30 (YE/GN or VT/WH) C972-3 GD137 (BK/WH) RH inner cab marker C973-1 CBP40 or CLS30 (YE/GN or VT/WH) C973-3 GD137 (BK/WH) RH outer cab marker C974-1 CBP40 or CLS30 (YE/GN or VT/WH) C974-3 GD137 (BK/WH) LH exterior mirror C521-5CBP40 (YE/GN) C521-7 GD137 (BK/WH) RH exterior mirror C601-5 CBP40 (YE/GN) C601-7 GD179 (BK/VT) LH rear (with pickup bed) C4035-2 CBP30 (YE/BU) C4035-1 GD176 (BK/WH) RH rear (with pickup bed) C4032-2 CBP30 (YE/BU) C4032-1 GD176 (BK/WH) LH rear (without pickup bed) C423-3 CBP30 (YE/BU) C423-2 GD176 (BK/WH) RH rear (without pickup bed) C422-3 CBP30 (YE/BU) C422-2 GD176 (BK/WH) Center rear lamp assembly (below tailgate) C4001-3 CBP30 (YE/BU) C4001-1 GD176 (BK/WH) LH rear side marker 1 C4094-1 CBP30 (YE/BU) C4094-2 GD176 (BK/WH) LH rear side marker 2 C4095-1 CBP30 (YE/BU) C4095-2 GD176 (BK/WH) RH rear side marker 1 C4096-1 CBP30 (YE/BU) C4096-2 GD176 (BK/WH) RH rear side marker 2 C4097-1 CBP30 (YE/BU) C4097-2 GD176 (BK/WH)
Is the voltage greater than 10 volts?
Yes
INSTALL a new bulb holder, cab marker lamp, rear lamp assembly or exterior mirror in question. TEST the system for normal operation.
No
REPAIR the ground circuit in question for an open. TEST the system for normal operation.
O7 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.