From the manual:
High Intensity Discharge (HID) High Beam Headlamps
Battery positive voltage is applied at all times to the coil and switched side of the high beam relay. Battery positive voltage is also applied at all times through the coil side of the low beam relay to the low beam relay control circuit, to the multifunction headlamp switch. When the multifunction headlamp switch is placed in the high beam position, battery positive voltage is applied through the high beam headlamp dimmer switch signal circuit to the BCM. The BCM then applies a ground to the high beam relay control circuit. This energizes the high beam relay, closing the switched side of the high beam relay, applying battery positive voltage to the Left and Right High Beam Fuses. Battery positive voltage is then applied from the High Beam Fuses through the high beam solenoid switched voltage supply circuit to the high beam solenoid assembly inside of the headlamp. This causes the solenoid to retract a plate partially covering the low beam headlamps and allowing the lamps to illuminate at full brightness.
Run Up Of The Lamp
Each ballast requires higher amperage in order to ensure normal startup and run up of the lamp. Run up is the term used to describe the extra power level given to the bulb. The input current during the steady state operation is lower that the start up amperage. After the lamp receives the strike from the starter and the arc is established, the ballast uses its operating voltage in order to provide the run up power needed in order to keep the lamp on. The lamp rapidly increases in intensity from a dim glow to a very high-intensity, bright light called a steady state. Within a few seconds of the arc being established in the bulb, the majority of steady state is complete. 100% of the steady state is completed shortly there after. A high watt power level is necessary in order to bring the lamp to a steady state in such a short period of time. The high watt power level allows the lamp to meet the SAE light vs. time specification.
When To Change The HID Bulb
Bulb failure, end of life occurs when the bulb gets old and becomes unstable. The bulb may begin shutting itself off sporadically and unpredictably at first, perhaps only once during a 24-hour period. When the bulb begins shutting itself off occasionally, the ballast will automatically turn the bulb back on again within 0.5 seconds. The ballast will re-strike the bulb so quickly that the bulb may not appear to have shut off. As the bulb ages, the bulb may begin to shut off more frequently, eventually over 30 times per minute. When the bulb begins to shut off more frequently, the ballast receives excessive, repetitive current input . Repetitive and excessive restarts or re-strikes, without time for the ballast to cool down, will permanently damage the ballast. As a safeguard, when repetitive re-strikes are detected, the ballast will not attempt to re-strike the lamp. The ballast then shuts down and the bulb goes out.
The following symptoms are the noticeable signs of bulb failure:
- A flickering light, caused in the early stages of bulb failure
- The lights go out, caused when the ballast detects excessive, repetitive bulb re-strike
- Color change - the lamp may change to a dim pink glow
Input power to the ballast must be terminated in order to reset the ballast's fault circuitry. In order to terminate the input power to the ballast, turn the lights off and back on again. Turning the lights off and back on again resets all of the fault circuitry within the ballast until the next occurrence of excessive, repetitive bulb re-strikes. When excessive, repetitive bulb re-strikes occur, replace the starter/arc tube assembly. The ballast will begin the start-up process when the starter/arc tube assembly is replaced. Repeatedly resetting the input power can overheat the internal components and cause permanent damage to the ballast. Allow a few minutes of cool-down time in between reset attempts.
Bulb failures are often sporadic at first, and difficult to repeat. Technicians can identify bulb failure by observing if the problem gets progressively worse over the next 100 hours of operation.
Light Color
White light has a different color rating than regular headlamps. The range of white light that is acceptable is broad when compared to halogens. Therefore, some variation in headlight coloring between the right and left headlamp will be normal. One HID at the end of the normal range may appear considerably different in color from one at the other end of the range. Difference in color is normal. Replace the arc tube only if the arc tube is determined to be at the bulb failure stage.
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