Pinpoint Test G: The Autolamps Are Inoperative

Autolamps

Pinpoint Test G: The Autolamps Are Inoperative

Refer to Wiring Diagram Set 85, Headlamps/Autolamps for schematic and connector information. [1][2]Diagrams By Number

Normal Operation

When the Smart Junction Box (SJB) detects the headlamp switch in the AUTOLAMPS ON position, the SJB (Smart Junction Box) monitors the light sensor input. The light sensor determines the amount of light based on the input received from the ambient lighting conditions. When the ambient level has reached a point (determined by the internal programming of the SJB (Smart Junction Box)), the SJB (Smart Junction Box) provides voltage to the headlamps, parking and license plate lamps.

This pinpoint test is intended to diagnose the following:

- Light sensor

- SJB (Smart Junction Box)

PINPOINT TEST G : THE AUTOLAMPS ARE INOPERATIVE

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 MANUAL HEADLAMP OPERATION

- Place the headlamp switch in the HEADLAMPS ON position.

Do the headlamps and parking lamps operate correctly?

Yes
GO to G2.

No
REFER to Headlamps Special Tool(s) Used With Diagnostics or Parking, Rear and License Plate Lamps Special Tool(s) Used With Diagnostics.

G2 CHECK FOR VOLTAGE TO THE LIGHT SENSOR

- Ignition OFF.

- Disconnect: Light Sensor C286 or C287.

- Ignition ON.

- Place the headlamp switch in the AUTOLAMPS ON position.

- For vehicles with automatic temperature control, measure the voltage between the light sensor C286-2, circuit VLF14 (BU/BN), harness side and ground.





- For vehicles with manual temperature control, measure the voltage between the light sensor C287-A, circuit VLF14 (BU/BN), harness side and ground.





Is the voltage approximately 5 volts?

Yes
INSTALL a new light sensor. REFER to Light Sensor . TEST the system for normal operation.

No
GO to G3.

G3 CHECK FOR CORRECT SJB (Smart Junction Box) OPERATION

- Disconnect all the SJB (Smart Junction Box) connectors.

- Check for:
- corrosion

- damaged pins

- pushed-out pins


- Connect all the SJB (Smart Junction Box) 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 SJB (Smart Junction Box). 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.