Dipped headlight but light is working???

[JeffM03]

Hey guys,

Just tried to get my car inspected, when the mechanic came over to tell me my headlight is out. Puzzled, I went out to the car with him and sure enough - left headlight was out. Fiddled around with it for awhile and couldn't get it to come back on. Annoyed, I left the shop and drove all 30 miles back to my house with the 'bulb out' indicator on the display. When I got home I turned off the car, turned it to ON, and flicked on the headlight. However, when I walked to the front of the car, both headlights were working.

To add more confusion to the mix: As I stood there, wanting to kick the car, I heard the oh-so-familiar screech that is the dash warning indicator noise. As I sat back in the car I noticed the 'left dipped headlight' message was still present, even though both headlights were working. I turned the car on/off, flicked the lights on/off, unplugged/replugged the left headlight, but still could not get the 'left dipped headlight' error to go away.

It's not the auto-level as I have removed fuse 10 due to a broken rear sensor, and as far as I know, it's not the bulb, ballast, or housing (these are D1S xenons, just so you know). Anyone got a remedy for this? I need to get my car inspected.

Cliff notes:

• D1S Xenon headlights
• Headlight out at inspection station
• Got home and headlight worked
• Display still showing 'dipped headlight'

[cosmokramer]

How do you know for certain that it isn't the bulb? Why don't you swap the left and right bulbs with each other to see if the error moves to the right side? If it doesn't, then swap ballasts...

I did this when I had the dipped headlight error on the right, and the error moved to the left along with the bulb when I swapped them...

[passatkid]

I have this same issue but only happens when cold and only once an awhile. Been having it for the last two year. Doesn't really bother me, but would interested to see what you find out.

[jayiszraw]

How do you know for certain that it isn't the bulb? Why don't you swap the left and right bulbs with each other to see if the error moves to the right side? If it doesn't, then swap ballasts...

I did this when I had the dipped headlight error on the right, and the error moved to the left along with the bulb when I swapped them...

why woud you swap ballasts? if its not the bulb its gotta be the ballast unless its another wiring issue.

[cosmokramer]

why woud you swap ballasts? if its not the bulb its gotta be the ballast unless its another wiring issue.

To be certain that the "dipped" error is caused by a faulty ballast. It would be a shame to drop 100+ on a new ballast when the one being replaced is perfectly fine....

[Dan1969]

the "dipped" headlight will not go away unless you reset with Vag-com. Your headlights are probably too close to your ABS sensor... there are some threads with the solution, grounding the wires somewhere so that the ABS doesn't interfeere with your headlights...

[JeffM03]

the "dipped" headlight will not go away unless you reset with Vag-com. Your headlights are probably too close to your ABS sensor... there are some threads with the solution, grounding the wires somewhere so that the ABS doesn't interfeere with your headlights...

Interesting. I'll have to take a look. Oddly enough, the error went away this morning and everything is working.

[CyberPMG]

It's more than likely that the ballast is starting to go bad. Could also be a loose wiring connection, but if you're running original bulbs and ballasts, chances are that they are starting to reach the end of their life. Fortunately, there's a good thread on here where you can pick up a new ballast for a lot less than from the dealer.

[JeffM03]

It's more than likely that the ballast is starting to go bad. Could also be a loose wiring connection, but if you're running original bulbs and ballasts, chances are that they are starting to reach the end of their life. Fortunately, there's a good thread on here where you can pick up a new ballast for a lot less than from the dealer.

Already did it. I actually helped contribute to that thread.

[Alphazuzu]

A month ago mine would alter left dipped then right but they would only stay off for that session of driving then come back on. I was mad one time and smacked the light it came right on and the dipped headlight error went away. so I would just try punching your headlight its a fail proof way of fixing the problem.

[JeffM03]

I'll be sure to do that if it happens again while at the inspection station.