Hids At Startup

[lsorah0001]

I know this has been debated for Silverados many many times...cut the wire to the light sensor (negating auto on) install a time delay relay under the dash (too much splicing for some, but works.) Don't the Escalades that have HIDs have their headlights stay on during startup? Is there some wiring difference, or is the relay in the under hood fuse box different? Does anyone know if there is something that Eskys have that Silvys do not that can be interchanged to have the headlights stay on during ignition, eliminating the on-off-on that plagues us now?

Thanks!

[lsorah0001]

A buddy of mine came by this morning that has a new Acura TL and his HIDs stayd on during the whole startup process...do Excalade have a different relay than Silverados do? Thoughts?

[Darkanion]

I had never noticed this until you mentioned it... And I think I figured out what I "normally" do differently than you. (But, maybe not.)

 

99% of the time, when I get in the truck, I don't stick the key in until I'm ready to start it. When I start it, I go straight from off to start. I don't pause at Accessory. When I do that, as the truck is starting, the parking lights come on, but the headlights do not come on until the truck fires up.

 

However, if I turn the key from off to Accessory, the AHL's kick-in and my headlgihts will come on (I have the DRL fuses removed from mine, so no DRL's). Then, when I go from Accessory to start, the headlights will blink off for a second and back on.

 

So, this may explain why your lights blink off and back on and some other people's do not. Perhaps they are hitting the starter quicker OR perhaps it has to do with the DRL fuses being removed OR a combination of the two...?

[lsorah0001]

I do that from time to time, but sometime forget. I saw an Escalade at Wally World one night that seemingly turned their key to acc (lights came on) then a few seconds later started the engine, with the headlights staying on...

[Darkanion]

I do that from time to time, but sometime forget. I saw an Escalade at Wally World one night that seemingly turned their key to acc (lights came on) then a few seconds later started the engine, with the headlights staying on...

Aren't HID's factory (or at least available from the factory) on the Escalades? It wouldn't surprise me if they have different circuitry to "keep" the lights on, during start up. I don't know what that extra circuitry might be. Until you figure it out and can get it retrofitted to your truck, I'd suggest trying to make a conscious effort to go straight from off to start... (Heck, *I* would probably just stick with doing that and save the $$ and trouble of trying to make something else work - but, that's just me.)

 

Let us know what you come up with!

[TedGEXT]

I have an Escalade EXT and checked this tonight. The HIDs come on and when you start they go off while the engine starts.

[jrrod2004]

Service Information

 

2008 Cadillac Escalade EXT | Avalanche, Escalade, Suburban, Tahoe, Yukon (VIN C/K) Service Manual | Document ID: 1671988 Exterior Lighting Systems Description and Operation

 

 

 

 

Low Beams - High Intensity Discharge (HID)

Normal operation of the HID system starts at the ballast. The headlamp ballast input connector receives battery positive voltage from fuses in the underhood fuse block. When the low beam headlamps are requested the low beam relay supplies voltage to the ballast on the right headlamp low beam supply voltage circuit and the left headlamp low beam supply voltage circuit, which in turn begins the low beam operation as follows. As soon as the input power is applied, the ballast draws 20 amps from the battery for 5-10 seconds, depending on the input voltage level. The ballast is then able to charge the 2 outputs leading to the start to -360 volts and +800 volts. Negative 360 volts and +800 volts are the voltages needed by the starter to strike or start the lamp. HID headlamps do not have filaments like traditional bulbs, instead, the starter uses a high voltage transformer to convert the +800 volts input power into 25,000 volts. The increased voltage is used in order to create an arc between the electrodes in the bulb. The creation of this arc begins the start up process.

 

 

Low Voltage Operation of HID Headlamps

The BCM monitors the vehicle system voltage while in the RUN power mode. When the system voltage drops below 8.9 volts, the following will occur:

 

 

• STAGE 1: If the low beam headlamps are ON, either manually or automatically, the BCM will turn ON the high beam headlamps by activating the High Beam output.

 

 

• STAGE 2: When the system voltage drops below 8.5 volts, the following will occur:

 

 

- If the low beam headlamps are currently ON, either manually or automatically, the BCM will turn OFF the low beam headlamps by deactivating the Low Beam output.

 

 

- If the headlamps are then turned ON manually, the manual switch redundancy will cause the low beam headlamps to remain ON.

 

If during the same ignition cycle, the BCM enters either STAGE 1 or STAGE 2 operations noted above, and then determines that the system voltage has risen, the following will occur:

 

 

• If the BCM has entered STAGE 2 operation, it will not return to STAGE 1 operation until the system voltage rises above 9.4 volts.

 

 

• If the BCM has entered STAGE 1 operation, it will not return to normal operation until the system voltage rises above 9.8 volts.

 

 

Electrical System Requirements with HID

Ensure that the battery and the harness are capable of supplying up to 20 amps of current per ballast, with less than 2 volts of system loss or voltage drop. Each ballast requires the 20 amps 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 from the -360-volt ballast output. The input current during the steady state operation is 3.4 amps at 12.8 volts.

 

 

Run Up of the HID Lamp

After the lamp receives the strike from the starter and the arc is established, the ballast uses its -360-volt output 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 2 seconds of the arc being established in the bulb, 70 percent of steady state is complete. 100 percent of the steady state is completed within 30 seconds. A 75-watt power level is necessary in order to bring the lamp to a steady state in the required period of time.

 

 

When to Change the HID Bulb

Bulb failure occurs when the bulb gets older 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 second. 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 (20 amps). 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:

 

 

• Flickering light caused in the early stages of bulb failure

 

 

• 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 ballasts 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 (w/HID)

HID headlamps have 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. A difference in color is normal. Replace the arc tube only if the arc tube is determined to be at the bulb failure stage.

[lsorah0001]

Wow, great info. I thought they stayed on, like the Acura...oh well. I guess we still have the time delay relay.

Thanks!