Pinpoint Test F: The High Beams Are Always On
Headlamps
Pinpoint Tests
Pinpoint Test F: The High Beams Are Always On
Refer to Wiring Diagram Set 85, Headlamps for schematic and connector information. Diagrams By Number
Normal Operation
The Instrument Cluster (IC) monitors the high beam request circuit from the multifunction switch by sending voltage signals on 2 circuits to the multifunction switch for the flash-to-pass request and for the high beam request.
When the multifunction switch is placed in the HIGH BEAM position, it passes through the FLASH-TO-PASS position first. When the multifunction switch is in the FLASH-TO-PASS position, the voltage signal for that circuit is routed to ground, indicating a request for the flash-to-pass feature. When the multifunction switch is placed in the HIGH BEAM position, both input circuits are routed to ground, indicating to the IC to change from the low beams to the high beams (or from the high beams to the low beams, if the high beams are already on).
Both input circuits to the IC must be grounded for the IC to switch from the low beams to the high beams, however, the flash-to-pass request must be received first.
The high beam relay coil is provided voltage when the ignition is in RUN. The IC provides ground for the high beam relay coil when the high beams are requested. The Battery Junction Box (BJB) fuse 8 (15A) provides voltage to the relay switch. When the relay is energized, voltage is provided to the high beams.
- DTC B1510 (Flash to Pass Switch Circuit Short to Ground) - an on-demand DTC that sets when the IC detects a short to ground from the flash-to-pass request input circuit.
- DTC B1568 (Lamp Headlamp High-Beam Circuit Open) - a continuous DTC that sets when the IC detects no voltage from the high beam relay coil ground controlled circuit (short to ground).
- DTC B2A23 (High Beam Input Circuit Short to Ground) - an on-demand DTC that sets when the IC detects a short to ground from the high beam request input circuit.
This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- High beam relay
- Multifunction switch
- IC
PINPOINT TEST F: THE HIGH BEAMS 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.
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F1 CHECK FOR DTC B1510 OR DTC B2A23
- Ignition OFF.
- Review the DTCs retrieved from the IC self-test.
- Is DTC B1510 or DTC B2A23 present?
Yes
GO to F2.
No
GO to F4.
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F2 CHECK THE MULTIFUNCTION SWITCH
- Disconnect: Multifunction Switch C202.
- Ignition ON.
- Enter the following diagnostic mode on the scan tool: IC Self-Test.
- Repeat the IC self-test.
- Is DTC B1510 or DTC B2A23 present?
Yes
GO to F3.
No
INSTALL a new multifunction switch. REFER to Steering Column Switches Steering Column Multifunction Switch. TEST the system for normal operation.
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F3 CHECK THE HIGH BEAM AND FLASH-TO-PASS REQUEST INPUT CIRCUITS FOR A SHORT TO GROUND
- Ignition OFF.
- Disconnect: IC C220a.
- Measure the resistance between the multifunction switch C202-8, circuit 91S-LE14 (BK/OG), harness side and ground; and between the multifunction switch C202-10, circuit 91S-LE25 (BK/BU), harness side and ground.
- Are the resistances greater than 10,000 ohms?
Yes
GO to F7.
No
REPAIR circuit 91S-LE14 (BK/OG) (high beam request) or circuit 91S-LE25 (BK/BU) (flash-to-pass request) for a short to ground. TEST the system for normal operation.
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F4 CHECK THE HIGH BEAM RELAY OUTPUT
- Ignition OFF.
- Disconnect: High Beam Relay .
- Ignition ON.
- Do the headlamps continue to illuminate?
Yes
REPAIR the high beam relay output circuit for a short to voltage. TEST the system for normal operation.
No
GO to F5.
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F5 CHECK THE HIGH BEAM RELAY
- Ignition OFF.
- Substitute a known good relay.
- Ignition ON.
- Do the headlamps continue to illuminate?
Yes
REMOVE the known good relay. GO to F6.
No
REMOVE the known good relay. INSTALL a new high beam relay. TEST the system for normal operation.
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F6 ISOLATE THE HIGH BEAM RELAY COIL GROUND CONTROLLED CIRCUIT FOR A SHORT TO GROUND
- Ignition OFF.
- Connect: High Beam Relay .
- Disconnect: IC C220a.
- Do the headlamps continue to illuminate?
Yes
REPAIR circuit 15S-LE12 (GN/YE) for a short to ground. TEST the system for normal operation.
No
GO to F7.
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F7 CHECK FOR CORRECT IC OPERATION
- Ignition OFF.
- Disconnect all the IC connectors.
- Check for:
- corrosion
- damaged pins
- pushed-out pins
- Connect all the IC 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 IC. REFER to Instrumentation and Warning Chimes Service and Repair. 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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