Driver's side headlights went out
 

Last night, I was driving home and had to slam on my brakes when the person in front of me stopped short. In doing so, my driver's side headlight (both high and low beams) went out! I'm quite sure that both worked immediately beforehand because my car had just been driven to me by the valet (very common in Houston) and I didn't notice anything off about it when I did the walk-around.

The passenger's side headlight still works on both levels. This past fall, I replaced the headlight switch with a used one after my headlights began flickering/not turning on (both headlights) and that had solved the issue. By the way, this is on a 2002 Porsche Boxster S with litronic headlights.

Has anyone encountered this problem? Could it be the headlight switch, or is that unlikely given that only one side has gone out? I'm thinking that the bulb may have shifted under heavy inertial load so I'll be checking fuses and the bulb today at lunch. Thanks for your input.

Just pull headlight out and make sure the plug is seated properly and place back in. I hit a pothole before and had same issue.

Agreed, I had a similar thing happen to me. I have Litronics and for some reason the high beams and fog lights went out but the low beam was okay. Turns out on Litronics the hi and fog have a separate connector to the light housing and it had worked loose some how. The main connection was fine.

Pull the entire housing and check the connections.

Thanks for the recommendations. I pulled out the driver's side headlight and inspected the two electrical connectors that connect the headlight assembly to the chassis; they looked fine.

I also removed the cover on the headlight assembly and checked the connections on the bulbs. I didn't go so far as to pull the bulbs out, but I confirmed that they were tight.

In addition, I checked the headlight fuses next to the pedals at the driver's feet and found that they were all intact.

To clarify, the driver's side headlights don't work at all (high beams, low beams, or fogs). This tells me it likely has to do with either the connections to the chassis or the control unit for the xenon system. Hopefully not the control unit given the cost.

Does anyone know how to diagnose the control unit to ensure that it hasn't gone bad?

Fixed! (as far as I can tell based on looking into the headlight in the hot and bright Texas sun)

Before ordering any parts, I wanted to re-check my work and found that while I had confirmed that the bulbs were connected well, I hadn't checked the ballast connection. It had come just slightly loose but wasn't off it's guide system so I missed it.

Thanks for everyone's input!

Hey all, since I last posted, my headlights have been working without issue, but a few weeks ago, I found that the passenger's side headlight was not turning on. I pulled it out, checked the bulbs, and found that the low beam bulb had burnt out. Replaced that. The high beam bulb (clear/blue color) however is not working properly as it does on the driver's side.

I checked the bulb and it is okay. I checked the ballast connection and it is okay.

In testing it out, I noticed that when I turn the headlights on, the light in question flickers briefly but doesn't stay on. I repeated this test and it kept happening, suggesting to me that the bulb isn't burnt out, but rather that there is a connection there that is loose or dirty.

At this point, I have two questions for you:
1) As I work to figure out how to fix this, is it bad for the car to drive it with the headlights on? The reason that I ask is that I don't want to risk burning out a good bulb on the driver's side if too much current goes through that bulb on account of a bad connection on the passenger's side.
2) Any recommendations for how to clean or otherwise fasten these connections more securely? I found that the plastic connector that you need to disconnect/reconnect when you're pulling the headlight assembly out of the car has broken, so I'm wondering if that is why the connection isn't sufficient. That being said, shouldn't the headlight be locked into place by the quarter-turn of the screw accessed in the front trunk?

Thanks for your help!

When I got my litronics to replace my previous halogens I had exactly that same issue. Cleaning my old switch with electrical cleaner fixed it sort of, and a new switch fixed it completely and haven't had the issue since then, and it has been a couple years.

There appears to be an aftermarket switch now that wasn't available a the time I got mine (or else I didn't find it) so I used OEM. Here is the aftermarket one... maybe you can be the first one to try it :)

Ok I was going to post a link to it from Rock Auto but it is out of stock... The other one they have is Airtex/Wells for $89.99, I seem to remember the one I saw that time was like $25 or $35.

Well now after looking at the Porsche part, maybe $89.99 was the discounted part. I was sure at one time they had one for $25-$35

This part has got to cross reference with an Audi or VW part...

Thanks for the quick response. Which switch are you referring to? Do you happen to know the part number?

Go to 101projects.com and go to Boxster, then to the replace headlamp switch article, it has instructions and part numbers.

Got it, thanks for clarifying.

So I actually already replaced the headlight switch last October with a used one from another 986 that I bought from Woody. Last time it was the driver's side headlight that was flickering and then not working, but this time it is the passenger's side headlight. Can the switch fail on either side like that?

Should I look into a new switch again, or did I just have bad luck this time and should go with another used one from Woody or another source?

I've just finished replacing the headlamp switch with a brand new one from Pelican Parts, but the passenger's side headlight is still flickering and not staying on.

Does anyone have any other ideas for what I can do at this point? I checked the connections on the headlight itself and they looked clean and functional. The headlight bulb looked good as well, although I'm not sure if I could tell if it was burnt out visually given that it's a litronic bulb and not just a simple filament.

Thanks for your help!

Power for the headlights passes through the switch as one, so if the headlight switch were bad, both headlights would have been affected.

The problem can only be in the wiring, fuse, connection or headlight if the other is working.

Try swapping the bulbs between the passenger and drivers side. If no change, swap them back to their original headlights, then swap ballasts. This will tell you if it's one of the two.

Also, if the connector is loose like you said, you need to fix that as its a common issue that can cause the symptoms you describe.