Autolamps

Special Tool(s)

	Fluke 77-IV Digital Multimeter FLU77-4 or equivalent
	Vehicle Communication Module (VCM) and Integrated Diagnostic System (IDS) software with appropriate hardware, or equivalent scan tool
	Flex Probe Kit 105-R025D or equivalent

Principles of Operation

NOTE: For the perimeter lighting feature, refer to Section 501-14 .

NOTE: The Smart Junction Box (SJB) is also known as the Generic Electronic Module (GEM).

Exterior Lighting

The SJB monitors the headlamp switch position by sending voltage signals on multiple circuits to the headlamp switch. There is one circuit for each headlamp switch position. At any given time, one of the signal circuits is switched to ground.

If the SJB does not detect any of the inputs to the headlamp switch is active (switched to ground) for 5 seconds, the SJB turns the parking lamps and headlamps on and keeps them on until the battery saver feature times out.

Additionally, if the SJB detects multiple headlamp switch input circuits short to ground, the SJB turns the parking lamps and headlamps on and keeps them on until the battery saver feature times out.

Refer to Exterior Lighting for information regarding the Battery Saver feature.

If the above situation occurs, the SJB cannot be ruled immediately as being at fault. This is normal behavior of the SJB design as it has detected a fault with the inputs from the headlamp switch.

Autolamps Feature

The SJB monitors the light sensor with a voltage reference signal. The light sensor input to the SJB varies with the ambient light conditions.

When the SJB receives an input from the headlamp switch indicating a request for the autolamps, the SJB monitors the light sensor for the ambient light condition. If the SJB determines the ambient light level is dark, the SJB supplies voltage to the exterior lamps.

If the ignition switch is already in the RUN position and the vehicle enters a dark/lighted area (such as when entering/exiting a non-lighted tunnel during the daytime), the transition from light to dark (or dark to light) needs to last 15 seconds before the SJB turns the exterior lamps on or off. This strategy is to prevent the exterior lamps from unnecessarily flashing on and off.

The SJB does react quicker under extreme light conditions. If the SJB has detected a very dark condition, the exterior lamps are turned on after 1.5 seconds. If the SJB has detected a very high ambient light level, the exterior lamps are turned off after 4 seconds.

Headlamps On With Wipers On Feature

If the headlamp switch is in the AUTOLAMPS ON position and the front wipers are on for more than 10 seconds (except during a mist wipe or while the wipers are on to clear washer fluid during a wash condition), the exterior lamps are turned on. The exterior lamps are turned off when the ignition switch is changed to the OFF or ACC position, the headlamp switch is placed in the OFF position, or the front wipers are off for more than 30 seconds. The exception to this is when the exterior lights are on because of darkness determined by the light sensor.

For diagnostics regarding the headlamps on with wipers on feature, refer to Section 501-16 .

Inspection and Verification

1. Verify the customer concern.

2. Visually inspect for obvious signs of mechanical or electrical damage.
   
   

     Visual Inspection Chart

   Mechanical	Electrical
   Headlamp switch	Wiring, terminals or connectors Light sensor Smart Junction Box (SJB)

   
   

3. If an obvious cause for an observed or reported concern is found, correct the cause (if possible) before proceeding to the next step.

4. NOTE: Make sure to use the latest scan tool software release.

   If the cause is not visually evident, connect the scan tool to the Data Link Connector (DLC).

5. NOTE: The Vehicle Communication Module (VCM) LED prove-out confirms power and ground from the DLC are provided to the VCM .

   If the scan tool does not communicate with the VCM :
   • Check the VCM connection to the vehicle.
   • Check the scan tool connection to the VCM .
   • Refer to Section 418-00 , No Power To The Scan Tool, to diagnose no power to the scan tool.

6. If the scan tool does not communicate with the vehicle:
   • Verify the ignition key is in the ON position.
   • Verify the scan tool operation with a known good vehicle.
   • Refer to Section 418-00 to diagnose no response from the PCM.

7. Carry out the network test.
   • If the scan tool responds with no communication for one or more modules, refer to Section 418-00 .
   • If the network test passes, retrieve and record the continuous memory DTCs.

8. Clear the continuous DTCs and carry out the self-test diagnostics for the SJB .

9. If the DTCs retrieved are related to the concern, go to the Diagnostic Trouble Code (DTC) Chart in this section. For all other DTCs, refer to the Diagnostic Trouble Code (DTC) Chart in Section 419-10 .

10. If no DTCs related to the concern are retrieved, GO to Symptom Chart .

Symptom Chart

Pinpoint Tests

Pinpoint Test G: The Autolamps Are Inoperative

Refer to Wiring Diagrams Cell 85 , Headlamps/Autolamps for schematic and connector information.

Normal Operation

When the Smart Junction Box (SJB) detects the headlamp switch in the AUTOLAMPS ON position, the SJB 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 ), the SJB provides voltage to the headlamps, parking and license plate lamps.

This pinpoint test is intended to diagnose the following:

• Light sensor
• SJB

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.

Pinpoint Test H: The Autolamps Are On Continuously

Refer to Wiring Diagrams Cell 85 , Headlamps/Autolamps for schematic and connector information.

Normal Operation

The Smart Junction Box (SJB) sends a voltage signal to the headlamp switch and light sensor.

When the headlamp switch is placed in the AUTOLAMPS ON position, the voltage signal is routed to ground. When the SJB detects the headlamp switch in the AUTOLAMPS ON position, the SJB 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 ), the SJB provides voltage to the headlamps, parking and license plate lamps.

This pinpoint test is intended to diagnose the following:

• Wiring, terminals or connectors
• Light sensor
• Headlamp switch
• Windshield wiper motor
• SJB

PINPOINT TEST H: THE AUTOLAMPS ARE ON CONTINUOUSLY

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