Pinpoint Test G: Low Beams Stay On When In High Beam Mode/Turn Off With The Flash-To-Pass Feature Active When Headlamps Are On

Headlamps

Pinpoint Test G: The Low Beams Stay On When In High Beam Mode/Turn Off With The Flash-To-Pass Feature Active When The Headlamps Are On

Refer to Wiring Diagrams Set 85, Headlamps for schematic and connector information. Electrical Diagrams

Normal Operation

The Battery Junction Box (BJB) fuse 18 (25A) supplies voltage to the low beam interrupt relay switch side at all times. The Central Junction Box (CJB) fuse 179 (7.5A) supplies voltage to the low beam interrupt relay coil when the ignition is in RUN. The Instrument Cluster (IC) controls the ground side of the low beam interrupt relay coil. When the low beam interrupt relay coil is energized, the low beam interrupt relay does not provide voltage to the low beam relay.

When the ignition is in RUN and the headlamp switch is not in the HEADLAMPS ON position, the IC (Instrument Cluster) provides ground for the low beam interrupt relay coil, energizing the relay to stop the flow of voltage to the low beam relay (the high beam relay still provides voltage to the low beam relay as a redundancy).

When the headlamp switch is placed in the HEADLAMPS ON position (and the IC (Instrument Cluster) is in the low beam state), the IC (Instrument Cluster) removes the ground from the low beam interrupt relay coil allowing voltage to flow from the low beam interrupt relay to the low beam relay.

If the multifunction switch is then placed in the FLASH-TO-PASS position, the IC (Instrument Cluster) energizes the high beam relay (the low beam interrupt relay is still de-energized), illuminating both the low and high beams simultaneously.

If the multifunction switch is then placed in the HIGH BEAM position (placing the IC (Instrument Cluster) in the high beam state), the IC (Instrument Cluster) energizes the low beam interrupt relay (the high beam relay is still energized from the flash-to-pass state) so that only the high beams are illuminated.

- DTC B1795 (Lamp Headlamp Low-Beam Circuit Open)- a continuous DTC that may set when the IC (Instrument Cluster) detects no voltage from the low beam interrupt relay coil ground controlled circuit (open or short to ground).

- DTC B1796 (Lamp Headlamp Low-Beam Circuit Short to Battery)- a continuous DTC that may set when the IC (Instrument Cluster) detects a short to voltage from the low beam interrupt relay coil ground controlled circuit.

This pinpoint test is intended to diagnose the following:

- Fuse

- Wiring, terminals or connectors

- Low beam interrupt relay

- IC (Instrument Cluster)

PINPOINT TEST G : THE LOW BEAMS STAY ON WHEN IN HIGH BEAM MODE/TURN OFF WITH THE FLASH-TO-PASS FEATURE ACTIVE WHEN THE HEADLAMPS ARE ON

NOTICE: Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may damage the connector.

G1 CHECK THE LOW BEAM INTERRUPT RELAY

- Ignition OFF.

- Disconnect: Low Beam Interrupt Relay.

- Substitute a known good relay.

- Ignition ON.

- Operate the flash-to-pass feature and the high beams with the low beams on.

Do the low beams stay on in the flash-to-pass mode and turn off in high beam mode?

Yes
REMOVE the known good relay. INSTALL a new low beam interrupt relay. TEST the system for normal operation.

No
REMOVE the known good relay. GO to G2.

G2 CHECK FOR VOLTAGE TO THE LOW BEAM INTERRUPT RELAY SWITCH SIDE

- Place the headlamp switch in the OFF position.

- Ignition OFF.

- Measure the voltage between the low beam interrupt relay pin 3, circuit 30-DA3 (RD), CJB (Central Junction Box) face side and ground.





Is the voltage greater than 10 volts?

Yes
GO to G3.

No
VERIFY the BJB (Battery Junction Box) fuse 18 (25A) is OK. If OK, REPAIR circuit 30-DA3 (RD) 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. Electrical Diagrams

G3 CHECK FOR VOLTAGE TO THE LOW BEAM INTERRUPT RELAY COIL

- Ignition ON.

- Measure the voltage between the low beam interrupt relay pin 1, circuit 15-LE36 (GN/WH), CJB (Central Junction Box) face side and ground.





Is the voltage greater than 10 volts?

Yes
GO to G4.

No
VERIFY the CJB (Central Junction Box) fuse 179 (7.5A) is OK. If OK, REPAIR circuit 15-LE36 (GN/WH) 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. Electrical Diagrams

G4 CHECK THE LOW BEAM INTERRUPT RELAY CONTROLLED GROUND CIRCUIT FOR A SHORT TO VOLTAGE

- Ignition OFF.

- Disconnect: IC (Instrument Cluster) C220A.

- Ignition ON.

- Measure the voltage between the IC (Instrument Cluster) C220A-8, circuit 15S-LE36 (GN/WH), harness side and ground.





Is any voltage present?

Yes
REPAIR circuit 15S-LE36 (GN/WH) for a short to voltage. TEST the system for normal operation.

No
GO to G5.

G5 CHECK THE LOW BEAM INTERRUPT RELAY COIL GROUND CONTROLLED CIRCUIT FOR A SHORT TO GROUND

- Ignition OFF.

- Measure the resistance between the IC (Instrument Cluster) C220A-8, circuit 15S-LE36 (GN/WH), harness side and ground.





Is the resistance greater than 10,000 ohms?

Yes
GO to G6.

No
REPAIR circuit 15S-LE36 (GN/WH) for a short to ground. TEST the system for normal operation.

G6 CHECK FOR VOLTAGE TO THE IC (Instrument Cluster)

- Connect: Low Beam Interrupt Relay.

- Ignition ON.

- Measure the voltage between the IC (Instrument Cluster) C220A-8, circuit 15S-LE36 (GN/WH), harness side and ground.





Is the voltage greater than 10 volts?

Yes
GO to G7.

No
REPAIR circuit 15S-LE36 (GN/WH) for an open. TEST the system for normal operation.

G7 CHECK FOR VOLTAGE TO THE LOW BEAM RELAY SWITCH SIDE WITH THE HIGH BEAM RELAY DISCONNECTED

- Ignition OFF.

- Disconnect: Low Beam Relay.

- Disconnect: High Beam Relay.

- Measure the voltage between the low beam relay pin 3, circuit 30-LE20 (RD), BJB (Battery Junction Box) face side and ground.





Is the voltage greater than 10 volts?

Yes
GO to G8.

No
REPAIR circuit 30S-DA3 (RD) for an open. TEST the system for normal operation.

G8 CHECK THE LOW BEAM RELAY SWITCH SIDE VOLTAGE SUPPLY CIRCUIT FOR A SHORT TO VOLTAGE

- Ignition OFF.

- Disconnect: Low Beam Interrupt Relay.

- Ignition ON.

- Measure the voltage between the low beam relay pin 3, circuit 30-LE20 (RD), BJB (Battery Junction Box) face side and ground.





Is any voltage present?

Yes
REPAIR the low beam relay switch side voltage supply circuit for a short to voltage. TEST the system for normal operation.

No
GO to G9.

G9 CHECK FOR CORRECT IC (Instrument Cluster) OPERATION

- Ignition OFF.

- Disconnect all the IC (Instrument Cluster) connectors.

- Check for:
- corrosion

- damaged pins

- pushed-out pins


- Connect all the IC (Instrument Cluster) 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 (Instrument Cluster). 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.