Pinpoint Test I: The Autolamps Are Inoperative

Autolamps

Pinpoint Test I: The Autolamps Are Inoperative

Normal Operation

When the Smart Junction Box (SJB) detects the headlamp switch in the AUTOLAMPS ON position (with the ignition on), 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 light 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.

The light sensor changes the voltage signal by increasing/decreasing the resistance to ground based on the ambient light level, thereby changing the voltage value of the signal. The higher the ambient light level, the lower the resistance to ground (and the lower the voltage reference signal appears to the SJB (Smart Junction Box)). The darker the ambient light level is, the higher the resistance to ground (and the higher the voltage reference signal appears to the SJB (Smart Junction Box)).

This pinpoint test is intended to diagnose the following:

- Light sensor

- SJB (Smart Junction Box)

PINPOINT TEST I : 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.

I1 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 I2.

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

I2 CHECK FOR VOLTAGE TO THE LIGHT SENSOR

- Ignition OFF.

- Disconnect: Light Sensor C286.

- Ignition ON.

- Place the headlamp switch in the AUTOLAMPS ON position.

- Measure the voltage between the light sensor C286-2, circuit VLF14 (BU/BN), harness side and ground.





Is the voltage approximately 5 volts?

Yes
INSTALL a new light sensor. REFER to Light Sensor . CLEAR the DTCs. REPEAT the self-test.

No
GO to I3.

I3 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. CLEAR the DTCs. REPEAT the self-test.