16 captured repliesDiscussion pagination complete · Source accounts, not a confirmed diagnosis
THIS DISCUSSION / SOURCE-DERIVED OVERVIEW
Discussion summary
YOUR RESEARCHleft headlight power issues?
Reported or suspected cause
connection at the headlight assembly socket
Suggestion or failed attempt
No successful repair reported for this finding.
0
Identified cause
1
Suspected cause
0
Reported fixes
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Suspected cause · Original poster
As it turns out I have one bad bulb and most likely the bad connection at the headlight assembly socket.
Leading evidence: 'connection at the headlight assembly socket' (no explicit attributable resolution; this is a reported action or suggestion). Across 1 matching discussions, the most frequently mentioned possible cause is 'connection at the headlight assembly socket' (1 discussions; 0 report identifying it and 1 suggest it). The most frequently discussed action is 'Check fuse a10' (1 discussions). For that action, 0 discussions report a resolution and 0 report an unsuccessful attempt. No action has an explicit, attributable resolution report under the current rules. These are forum reports and suggestions, not a confirmed diagnosis.
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Suggestion
I meant remove the fuse and check the source pin (on the fuse socket) to make sure the fuse gets power (+12v) from the switch when you turn the switch to the low beam position.
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Suggestion · Original poster
It doesn't matter if I have the high beam or low beam selected nor does the turn signal change where power is detected.
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Suggestion · Original poster
Ok, I thought I was being thorough but I wasn't paying attention to when I had the key turned on or not when I was testing initially....
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Suggestion
I meant remove the fuse and check the source pin (on the fuse socket) to make sure the fuse gets power (+12v) from the switch when you turn the switch to the low beam position.
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16 eligible posts · 0 unverified posts · 1 discussions match the subject in their title or opening post.
Rennlist: 1 discussions
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Generation: 20261026T220748Z · outcome-qualification-6. Deterministic extraction; no AI model inference. How we use sources
I have a 2003, 996, US model C4.
The driver side headlights do not come on, The turn signal does not come on. The side marker does come on. The turn signal indicator blinks rapidly if I select a left turn.
On the right side everything works as designed.
I have removed the headlight and tested the connection socket where the light assembly slides in and connects the circuits.
There are two ground wires there and both of them test as good by putting a test lamp between them (one ground at a time) and positive on the battery.
Of the other pin locations in that connection socket there is only one pin that has 12 volts potential to ground when the light switch is in the on position. It doesn't matter if I have the high beam or low beam selected nor does the turn signal change where power is detected.
I think, if I read the diagram correctly, that there should be at least two wires providing power to the light assembly. But perhaps that was supposed to be after the one wire fed power to the assembly. I haven't figured out how to understand the symbols indicating connectors and where they are in the car etc.
Can anyone tell me what I should be finding as far as power to those pins and under which switch positions they would be 'hot'?
The way the socket is oriented it is 2 rows of 6 pins one row over the other. Standing at the front facing the socket the grounds are top left and bottom right and the one pin that I have power to right now is second from left on the bottom row.
Have you checked fuse A10? The socket pins (the car side) are 1-6 bottom row from left to right and 7-12 top row right to left. Your grounds on pins 6 and 12 are fine. You also got power on pin 2 which powers the left side market light. You need power on pin 11 for low beam, which is supplied by fuse A10.
If it's not the fuse, the light switch is a strong suspect.
Fuses are good.
I guess I have to remove wheel to get access to back side of the socket/plug location to ensure proper fit.
Does anyone have the pin out diagram of X 1/1 connector? It's the 21 pin white connector on sidewall near brake reservoir. It feeds the left headlight...if the power from the switch isn't present there on its way to the connection at the headlight assembly then I can avoid pulling wheel to inspect that possibility.
I don't know which pins at X 1/1 should have what...
I don't know but I added wire colors below to help. Also, you may want to unplug fuse A10 and check if you get 12v there when the light switch is turned on for low beam. If you do, the next stop is the x1/1 connector like you said, the only connection between the fuse and the left light socket.
X1/1 pins:
#1->low beam Yellow/black
#2->high beam Yellow/white
#3->side marker Gray/black
#4->turn signal Black/white
#5->fog light White/black
Not sure I follow that.
Do you mean check for 12volts at the load side of the removed fuse location when switched to low beams?
As in, 12 volts potential feeding back towards what would be the 'output' of that fuse normally?
I meant remove the fuse and check the source pin (on the fuse socket) to make sure the fuse gets power (+12v) from the switch when you turn the switch to the low beam position.
If power gets to the fuse, you can eliminate the light switch and trace further downstream toward the x1/1 and the headlight.
Power flow: battery->light switch->fuse A10->x1/1->low beam
lol thanks I was having a dumb moment...so the switch controls that fuse instead of it being constant power....
I never realized that was a possibility. I assumed power->fuse->switch..,etc...
Many thanks!
Went through this. Did you take out the fender well to seat it enough?
After you have the light out you can take the connector off the back of the mount. Three is enough play that you can test the light and make sure it is a seating issue before removing the wheel well liner
Ok, I thought I was being thorough but I wasn't paying attention to when I had the key turned on or not when I was testing initially....
After trying the X 1/1 connector I realized I do have power where it should be.
As it turns out I have one bad bulb and most likely the bad connection at the headlight assembly socket.
Many thanks for the help to all of you!
Your assistance helped me save a couple hundred dollars.
Same issue, and just about to go through the same troubleshooting... what do you mean a bad connection at the headlight assembly? Did you have to fix anything there?
Thanks
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