Pinpoint Test D: The High Beams Are Always On
Headlamps
Pinpoint Test D: The High Beams Are Always On
Refer to Wiring Diagram Set 85, Headlamps for schematic and connector information Electrical Diagrams.
Normal Operation
Voltage is provided at all times to the switch and coil sides of the high beam relay. The Body Control Module (BCM) sends two voltage signals to the multifunction switch. One is to monitor for a high beam request and the other for a flash-to-pass request. The multifunction switch routes the corresponding voltage signal to ground when placed in the HIGH BEAM or FLASH-TO-PASS position. When the headlamps are on and the BCM (Body Control Module) detects a request for the high beams or flash-to-pass feature, the BCM (Body Control Module) provides ground for the high beam relay coil. When the high beam relay energizes, voltage is routed through Battery Junction Box (BJB) fuses 37 (10A) (LH high beam) and 38 (10A) (RH high beam) to the headlamps.
- DTC B1007:92 (High-Beam Headlamp Switch: Performance Or Incorrect Operation)- an on-demand DTC that sets when the BCM (Body Control Module) detects a short to ground from the high beam or flash-to-pass request input circuits.
- DTC B109A:14 (High Beam Relay: Circuit Short To Ground Or Open)- a continuous and on-demand DTC that sets when the BCM (Body Control Module) detects a short to ground from the high beam relay coil ground controlled circuit.
This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- High beam relay
- Multifunction switch
- BCM (Body Control Module)
PINPOINT TEST D : THE HIGH BEAM(S) ARE ALWAYS ON
NOTICE: Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may damage the connector.
D1 CHECK THE MULTIFUNCTION SWITCH INPUT
- Ignition ON.
- Enter the following diagnostic mode on the scan tool: BCM (Body Control Module) DataLogger.
- Monitor the BCM (Body Control Module) multifunction switch high beam and flash-to-pass PIDs (HIGH_BEAM_SW, FLASH-to-PASS).
Does either PID indicate a high beam or flash-to-pass request?
Yes
GO to D2.
No
GO to D4.
D2 CHECK THE MULTIFUNCTION SWITCH
- Ignition OFF.
- Disconnect: Multifunction Switch C202A.
- Ignition ON.
- Enter the following diagnostic mode on the scan tool: BCM (Body Control Module) DataLogger.
- Monitor the BCM (Body Control Module) multifunction switch high beam and flash-to-pass PIDs (HIGH_BEAM_SW, FLASH-to-PASS).
Does either PID indicate a high beam or flash-to-pass request?
Yes
GO to D3.
No
INSTALL a new multifunction switch. TEST the system for normal operation.
D3 CHECK THE HIGH BEAM AND FLASH-TO-PASS INPUT CIRCUITS FOR A SHORT TO GROUND
- Ignition OFF.
- Disconnect: BCM (Body Control Module) C2280E and C2280F.
- Measure the resistance between the multifunction switch C202A-5, circuit CLF27 (GN/BN), harness side and ground; and between the multifunction switch C202A-10, circuit CLF17 (WH/OG), harness side and ground.
Are the resistances greater than 10,000 ohms?
Yes
GO to D8.
No
REPAIR circuit CLF27 (GN/BN) (flash-to-pass) or circuit CLF17 (WH/OG) (high beam) for a short to ground. TEST the system for normal operation.
D4 CHECK THE HIGH BEAM RELAY OUTPUT
- Ignition OFF.
- Disconnect: High Beam Relay.
- Ignition ON.
Do the high beams continue to illuminate?
Yes
GO to D5.
No
GO to D6.
D5 ISOLATE THE SHORT TO VOLTAGE
- Disconnect: BJB (Battery Junction Box) Fuses 37 (10A) and 38 (10A).
Does either high beam continue to illuminate?
Yes
REPAIR circuit CBB37 (WH) (LH headlamp) or circuit CBB38 (GY/BN) (RH headlamp) for a short to voltage as necessary. TEST the system for normal operation.
No
REPAIR circuit CLF08 (YE/VT) for a short to voltage. TEST the system for normal operation.
D6 CHECK THE HIGH BEAM RELAY
- Ignition OFF.
- Substitute a known good relay.
- Ignition ON.
Do the high beams continue to illuminate?
Yes
REMOVE the known good relay. GO to D7.
No
REMOVE the known good relay. INSTALL a new high beam relay. TEST the system for normal operation.
D7 CHECK THE HIGH BEAM RELAY COIL GROUND CONTROLLED CIRCUIT FOR A SHORT TO GROUND
- Ignition OFF.
- Disconnect: BCM (Body Control Module) C2280D.
- Measure the resistance between the high beam relay pin 2, circuit CLF02 (GY/BN), BJB (Battery Junction Box) face side and ground.
Is the resistance greater than 10,000 ohms?
Yes
GO to D8.
No
REPAIR circuit CLF02 (GY/BN), for a short to ground. CLEAR the DTCs. TEST the system for normal operation.
D8 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.