Steve_R

I am NOT an expert on HID lights so I searched and read a bit about longevity. Seems newer HID headlights and ballasts should last 6,000-8,000 hours. I found no mention about repeated cycling reducing that. If that's true the 5 minutes or less they're on because of the auto-on feature isn't something to worry about.

4thC4at60

I had my C6 for 7 years and 123,000 miles - no bulb failure
I now have had my C7 for two years and 34,000 miles - no bulb failure

In my experience you're worrying about nothing.

ersatz928

HID bulbs do have a long life, but that is based on continuous hours of operation, however there is a significant life factor for turning then on and off. If these bulbs were easy to change, I wouldn't really care...but they are not on the C7.

From Wikipedia :
"End of life : Factors of wear come mostly from on/off cycles versus the total on time. The highest wear occurs when the HID burner is ignited while still hot and before the metallic salts have recrystallized."

And yes, I do keep my cars for a long time...I still have my C5 that I bought in 2001.......

yeller z06

I had to diagnose and repair the Xenon (HID) bulbs in the wife's BMW years ago, and learned that there are three components: the ballast, a starter and a bulb. Not unlike the old fluorescent lights. In order to figure out what went wrong, I swapped parts left-to-right until I found it, and it was the starter. Her car had auto headlights and would come on every time she entered or exited the garage, just like these guys are complaining about.

In the case of these poor C7 owners who will have premature failure, I would suspect that it would be the starter that goes bad. It was something like $70 for the BMW, which means that it should be at least half that for the Chevy.

Natch, diagnosing it is the hard part. The dealers generally don't bother, and instead recommend swapping out the entire $1000 headlight assembly.

But hey, if worrying about a car's shortened headlight lifespan is your biggest concern these days, then I want your life.

ersatz928

Not a major issue in my life, but most cars with auto headlights give you the option to disable it....once....not everytime you start it....

Diesel man

Mine turns on the lights when I drive through a shadow. Big pain!. It would be nice if they were less sensitive

Elk

^^^
Why is this "Big pain"? The lights turn off automatically as well.

It is a bit of unnecessary wear however.

Diesel man

Dash lights dim way down at the same time the headlights come on...

eboggs_jkvl

Depends on the settings you use for "way down". I like them bright so the switch is not a big deal either direction.

Elmer

Gearhead Jim

When I start our C7 in the garage, I twist the headlight switch to the Off position just before hitting Start. After it starts, I release the switch and the lights stay off.
After I back out of the garage, twist the switch again and the daytime running lights come on.
When returning to the garage, twist them Off just before entering.

The C6 will tell you if your lights are Off when they should be on, but the C7 deleted that in another "WTF were they thinking?" move.

Mad*Max

Interesting, in Canadian cars you can't defeat the auto-on, once you slap the car into gear the lights come on no matter what.

ZO6LIFE

Here's how you fix it...
take a dremel and carefully open up the back of the switch. Once it's open you will see the spring that holds the switch in the "auto" position. Remove or disable the spring, close up the switch with an adhesive and install it in the dash. YOU'RE DONE!!
By disabling the spring your switch will now stay in the "off" position. You now have totally manual lights again.
if you want, you can wire up the hockey stick lights and make those manual as well. Off and on anytime you want.

I did this on my supersport and it works like a charm. Once it warms up the C7 will get this free mod too.

Gearhead Jim

Interesting, thanks. Once you go into gear and after the lights come on, can you twist the switch again and make them go out at that point?
Long ago, someone stated that US cars must have a way to manually turn off the headlights, it was something to do with military bases or blackouts.
I'm not sure if that's really true.

Mad*Max

not in the newer GM cars, in the older models from the 90s as long as you didn't put the handbrake all the way down you could trick the lights to stay off

Vetteman Jack

I too have not really given this much thought. I start the car and drive away - if it is daylight, I do not really notice the lights are on since I back into my garage and when the door opens the lights are not noticable. If it is dark, the lights are needed anyway.

aklim

And why are we going through all that for again? Is there a lot of gain?

Gearhead Jim

^^^
Headlight repairs can be expensive and inconvenient.
I'm waiting for someone to conduct a double blind controlled study on whether my technique actually extends the headlight life.
Until the study is peer reviewed and published, I'll just turn them Off in the garage and back to Auto after I exit.

Some people wire a small spotlight into their garage door opener, aimed to shine on the headlight sensor. Sometimes that's enough to keep the lights out in the garage, sometimes the lights come on as soon as you back out of the spotlight beam. That would also be a nice topic for further study.

aklim

Well, it is expensive since you have to pull the front cover but if I do, I will convert it to LED if possible. Probably change both bulbs at the same time. As to the extension of the life, the question becomes "how much"? Seeing as it is expensive, I don't see a lot of people whining about it so I am not sure it is a very frequent thing like it is with incandescent bulbs. IF it blows out once in the next 15 years? I probably won't care. "Cost of doing business" would be my attitude and "Somebody Else's Problem" would also come into play. So probably not interested in saving it for the next guy by wasting my effort. The lifespan is about 2500 hours so if it gives me 20 more hours, is it worth it? Marsauto supposedly gives 3500 hours. So unless it can give me a double lifespan, I'm not sure how it is worth it. Also you would have to weigh it against changing the switch that you keep twitching. In 10 years, I can get the bulb but can we get the switch? Hard to say.

Gearhead Jim

^^^
With lots of electronics, the on-off cycles are just as important as the actual run time.
When somebody does the controlled study we've discussed, then perhaps we'll know.
After doing it a few times, the "twist off and hold before starting" thing becomes as automatic as fastening the seat belt is for me, and a lot easier.

aklim

I don't know who would do a controlled study since we don't have someone who will profit from it. If nobody will do a study of the snake oils we put into the gas and rely on testimonials which are fraught with imagination, I don't believe it is in anyone's interest to do it and therefore it won't be done.

I usually leave the seatbelt locked if there are a lot of "in and out". In my case, getting the wife to buy into that and executing it perfectly wouldn't be worth the teaching aggravation. Also, I am a big fan of "set it and forget it". Wife's 2010 MB has 100K and autohead lights. Self leveling and probably similar construction bulb. I don't hear many people grumbling about how often their bulb fails either.

Do you think the switch has as good a life as the bulb considering you fiddle with it a couple times a trip? Like I said, I can get the bulb in 10 years time. I can't be sure GM won't "obsolete" the switch now that the C7 is done and we are in year 3 of the C8 run.