The concept of an automatic headlight dimming system is nothing new, as far back as the late '50s we were using a system on some of our vehicles to handle this responsibility. Problem was the units needed to carry this out were the size of your average third grader and just about as reliable. Automotive engineering would not accept defeat, no sir! They kept at it until now we have the Intellibeam System. Much more compact and reliable than its earlier predecessor, Intellibeam will be making its debut on the 2005 Cadillac STS. Let's take a closer look...
The system consists of a digital light sensor that is located in a separate module that is mounted to the back of the inside rearview mirror. The digital sensor detects light, not vehicle movement. The sensor analyzes light color, intensity, and movement. There is, however, a discreet line to the Intellibeam digital sensor that does provide vehicle speed. The headlamp switch must in the AUTO position in order for it to work. The Intellibeam system will turn OFF the high beam headlamps when other vehicles' headlamps or taillights are detected by the digital sensor. Intellibeam can be deactivated when the headlamp dimmer switch is moved from the neutral position to the high beam or flash to pass (FTP) positions. When the headlamp dimmer switch is returned to the neutral position, Intellibeam will be enabled.
Intellibeam modulates the high beam headlamps by gradually fading the high beam headlamps ON or OFF. In the illustration above, vehicle "A" headlights are in the sensing area of Intellibeam (dashed green line), so the sensor will command the module to dim the high beams. When the oncoming vehicle reaches point "B" the high beams will come on again. When the sensor detects taillights like those on car "C", it will also turn off the high beams. Intellibeam is designed to ignore non-vehicular light sources. However, the system may dim the high beams if it detects lighting or lighting reflections similar in color and intensity to vehicle lighting. When this occurs, Intellibeam will dim the high beams until the light or reflection source is no longer detected.
Intellibeam may not operate properly if any of the following conditions exist:
 | The other vehicles lamps are undetectable due to dirt, snow, road spray, smoke, fog, or any other airborne conditions. |
| The vehicle windshield is covered with ice, dirt, snow, haze, or the Intellibeam digital light sensor is obstructed. |
| The vehicle ride height is such that the front of the vehicle is pointed upward causing the Intellibeam light sensor to be aimed high. |
| The vehicle is being driven on winding or hilly road conditions which would make any on coming vehicle headlamps undetectable by the Intellibeam. |
Cleaning the Intellibeam digital light sensor should be done periodically to ensure system performance. To clean the sensor, use glass cleaner and a soft cloth. Apply the glass cleaner to a soft cloth and gently wipe the light sensor lens. Do not apply the glass cleaner directly to the light sensor lens.
As mentioned previously, the
vehicle speed plays a role in Intellibeam's operation. This is accomplished
through a discreet vehicle speed signal line. Below is an explanation of what
the speeds mean to system operation.
Speed Thresholds:
| Accelerating: As the vehicle is accelerating, Intellibeam will gradually apply the high beams when vehicle speed reaches 20 MPH or greater. Full high beam intensity will not occur until the vehicle has achieved a speed of 25 MPH or greater. |
| Decelerating: As the vehicle is decelerating, Intellibeam will fade the high beams down until they are completely OFF at or below 15 MPH. |
| The high beam indicator located on the instrument panel cluster (IPC) will turn ON as soon as the high beams are energized even thought full intensity has not been achieved. The high beam indicator will not turn OFF until the high beams have faded completely OFF. |
The Intellibeam demonstration mode allows the technician to verify that the Intellibeam system components are operating correctly. Perform the Intellibeam demonstration mode under daylight conditions only. The steps to perform this are in SI, make sure to follow them correctly, to avoid unnecessary repairs and to "Fix it Right the First Time".
Mik Stubing Lead Instructor - Northeast Region
