David George

My low beams on left and right side went out on my '03 Boxster S

The wiring harness inside my headlights were cracked/brittle and exposing the copper. Thinking this was the culprit, I removed the harness from the plastic headlight housing and rewired everything.

I made sure all lights worked before putting the harness back inside the housing.

When it came to the moment of truth, I was right back where I started. High beams, tuns signals, fogs lights, and city lights all work - but, still no low beams.

The only possible explanation is that the headlight pins are not properly inserting into the socket when installing the housing.

So I took the harness back out. I have half a mind to just de-pin the socket for the low beams on the body harness and drill a hole directly into the headlight housing with a ton of extra wire.

Before I go with that hack job nuclear method, I'm checking here for better plans.

Thanks in advance for your thoughts.

tcora

I assume this means that you applied power to the connector terminals on the back of the headlight assembly? Is that correct?

Have you verified that there is low beam power making it to the vehicle side connector which mates to the one on the headlight assembly?

This is a head scratcher, if the answer is yes…

jbauer

I'm sure you checked the fuses, right? 🤔

teejerdude

David George, you may on the right track when you say: “The only possible explanation is that the headlight pins are not properly inserting into the socket when installing the housing.”

I had a similar (but not exactly the same) issue that may be relevant with my driver’s side headlight. For this discussion, there were three parts involved:

1. Headlight Electrical Harness Connector (blue plug): Part # 99965015040

2. Headlight Bracket: Part # 9966310410

3. Headlight Fastener (yellow clip): Part # 99663124600

When I purchased my 2002 Boxster, the headlight bracket around the yellow clip was broken, the yellow clip was missing, so the blue plug was very loose in the headlight bracket. The only way to get the headlight to work properly was to reach around the back of the headlight and manually plug in the blue plug into the headlight before reinstalling the headlight.

I replaced the headlight bracket, but the yellow clip would not hold the blue plug firmly. Turned out the blue connector also had broken plastic on the sides and would not properly slide in and fit firmly in the headlight bracket when the yellow clip was engaged. With the blue plug still not fitting firmly in the headlight bracket, the blue plug would not align properly and plug into the headlight when reinstalling the headlight.

Next I purchased a new blue plug, had to re-pin the blue plug into the headlight harness, and then the new blue plug fit properly into the headlight bracket, the blue plug could be secured firmly with the yellow clip, and then the blue plug would properly align with the electrical connector on the back of the headlight and everything worked perfectly after that.

If your headlights work fine when you manually plug them into the blue plug but do not work properly when you have the blue plug installed in the headlight bracket with the yellow clip engaged, then check to make sure the blue plug is being held very firmly in the headlight bracket. Also, you mentioned that you rewired the harness inside your headlights, so it’s possible the socket where the electrical pins are located on the back of the headlights got slightly shifted out of alignment.

So, recommend making sure the electrical sockets where the pins are located are properly installed in the back of the headlights. There is little room for error on the tolerances of the connection between the blue plug and the headlights when reinstalling the headlights. If everything does not align perfectly, the interplay and alignment between the three parts above and the electrical sockets where the pins are located in the back of the headlights is the likely problem.

David George

Thanks for the responses.

I sorted it out by screwing the harness plug back into the plastic housing with one washer on each screw. I water proofed it with some 3M foam tape (double sided adhesive). Making the plug protrude just a tiny bit more on the plastic housing allowed contact to be made with the bottom set of pins and WALLA! I've got low beams.