Pinpoint Test A: Both High Beams Are Inoperative
Headlamps
Pinpoint Tests
Pinpoint Test A: Both High Beams Are Inoperative
Refer to Wiring Diagram Set 85, Headlamps/Autolamps for schematic and connector information. Diagrams By Number
Normal Operation
The Lighting Control Module (LCM) and the multifunction switch are supplied voltage from the Central Junction Box (CJB) through circuit 910 (PK). Ground is provided to the multifunction switch through circuit 57 (BK). The LCM sends a 5-volt reference signal to the multifunction switch through circuit 12 (LG/BK).
When the multifunction switch is placed in the FLASH-TO-PASS position, the battery voltage from circuit 910 (PK) is routed to the LCM through circuit 12 (LG/BK), pulling the signal high. When the multifunction switch is placed in the HIGH BEAM position, the signal from circuit 12 (LG/BK) is routed to ground through circuit 57 (BK), pulling the signal voltage low. When the LCM detects ground or the higher voltage, the LCM provides voltage to the high beam headlamps.
This pinpoint test is intended to diagnose the following:
- Fuse
- Wiring, terminals or connectors
- Multifunction switch
- LCM
PINPOINT TEST A: BOTH HIGH BEAMS ARE INOPERATIVE
NOTICE: Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may damage the connector.
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A1 CHECK THE HIGH BEAM INDICATOR OPERATION
- Ignition ON.
- Place the headlamp switch in the HEADLAMPS ON position.
- Place the multifunction switch in the HIGH BEAM position.
- Does the high beam indicator illuminate?
Yes
GO to A5.
No
GO to A2.
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A2 BYPASS THE MULTIFUNCTION SWITCH
- Place the headlamp switch in the OFF position.
- Ignition OFF.
- Disconnect: Multifunction Switch C202a.
- Connect a fused jumper wire between the multifunction switch C202a-10, circuit 12 (LG/BK), harness side and C202a-9, circuit 57 (BK), harness side.
- Ignition ON.
- Place the headlamp switch in the HEADLAMPS ON position.
- Is the high beam indicator illuminated?
Yes
REMOVE the jumper wire. INSTALL a new multifunction switch. CLEAR the DTCs. REPEAT the self-test.
No
REMOVE the jumper wire. GO to A3.
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A3 CHECK FOR VOLTAGE TO THE MULTIFUNCTION SWITCH
- Measure the voltage between the multifunction switch C202a-10, circuit 12 (LG/BK), harness side and ground.
- Is the voltage approximately 5 volts?
Yes
REPAIR circuit 57 (BK) for an open. TEST the system for normal operation.
No
GO to A4.
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A4 CHECK CIRCUIT 12 (LG/BK) FOR AN OPEN
- Place the headlamp switch in the OFF position.
- Ignition OFF.
- Disconnect: LCM C2145d.
- Measure the resistance between the multifunction switch C202a-10, circuit 12 (LG/BK), harness side and the LCM C2145d-26, circuit 12 (LG/BK), harness side.
- Is the resistance less than 5 ohms?
Yes
GO to A6.
No
REPAIR the circuit. TEST the system for normal operation.
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A5 CHECK CIRCUIT 910 (PK) FOR AN OPEN
- Place the headlamp switch in the OFF position.
- Ignition OFF.
- Disconnect: LCM C2145c.
- Measure the voltage between the LCM C2145c-1, circuit 910 (PK), harness side and ground.
- Is the voltage greater than 10 volts?
Yes
GO to A6.
No
VERIFY the CJB fuse 24 (15A) is OK. If OK, REPAIR the circuit for an open. TEST the system for normal operation. If not OK, REFER to the Wiring Diagrams to identify the possible causes of the circuit short.
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A6 CHECK FOR CORRECT LCM OPERATION
- Ignition OFF.
- Disconnect all the LCM connectors.
- Check for:
- corrosion
- damaged pins
- pushed-out pins
- Connect all the LCM 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 LCM. 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.
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