Autolamps

Autolamps

Principles of Operation

NOTE: For the headlamps on with the wipers on feature, refer to Wiper and Washer Systems.

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

The SJB (Smart Junction Box) 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 routed to ground.

If the SJB (Smart Junction Box) does not detect any of the inputs to the headlamp switch are active (routed to ground) for 5 seconds, the SJB (Smart Junction Box) turns on the exterior lights and keeps them on for 10 minutes after the ignition switch is turned off (or 10 minutes from the time the SJB (Smart Junction Box) does not detect any headlamp switch input if the ignition switch was already off). Additionally, if the SJB (Smart Junction Box) detects multiple circuits short to ground, the SJB (Smart Junction Box) implements a planned strategy depending on the inputs received. Based on the inputs received, the autolamps, the headlamps and/or the parking lamps are turned on.

If either of these situations occur, the SJB (Smart Junction Box) Cannot be ruled immediately as being at fault. This is normal behavior of the SJB (Smart Junction Box) design as it has detected a fault with the inputs from the headlamp switch.

The SJB (Smart Junction Box) also monitors the light sensor with a voltage signal. The light sensor input to the SJB (Smart Junction Box) varies with the ambient light conditions.

When the SJB (Smart Junction Box) receives an input from the headlamp switch indicating a request for the autolamps, the SJB (Smart Junction Box) monitors the light sensor for the ambient light condition. If the SJB (Smart Junction Box) determines the ambient light level is dark, the SJB (Smart Junction Box) 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 (Smart Junction Box) turns the exterior lamps on or off. This strategy is to prevent the exterior lamps from unnecessarily flashing on and off.

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