H5 to H4 headlight conversion
 

Does someone offer a H5 to H4 wiring adaptor for the bulb or do I need to cut and splice wires? I hate to hack wires if I don't have to. TIA! ;)

There are adapter harnesses available at most auto-supply houses.

As Brian indicates, some have had luck finding pre-made adapters. Myself, I was unable to locate any, so did the cut-n-splice.

Bill Ball has a great write-up on his website, but I can't locate it right now. Bill - if you read this, perhaps add a link to your 'Workshop' site in your forum sig?

Cut and splice for me too.

I have not seen any adapter harnesses, and the H4 plugs from the part house are not the best - they have no rubber boot. So, it would be best if you got the plugs and boots from a Euro harness. I wrapped it in some waterproof tape. Not the best, but no problems despite driving the car in the rain for 3 years since the conversion.

Anyway, here is my write-up.
http://www.billsworkshop.com/P928S4/h5toh4/h5toh4.htm

Thanks for the info guys and nice write up Bill. I'll use it when I install them. I'll search for an adaptor but it doesn't look promising. I'll do my best with solder and heat shrink to make it look as professional as possible.

Pelican and AJusa both sell an H5 to H4 adapters.

Thanks for the reply Anthony. But I called both and neither sell an actual "H4 to H5 plug adaptor." Pelican sells a wiring harness for the H4 and AJ's sells a H4 plug kit. This looks like the best way to go though. It's just a H4 plug with the bare prongs. So I cut off my H5 plug, strip the wires and insert them into the bare prongs. Then push the prongs into the plug. This way I only use the factory wiring and get a factory look. BTW, beautiful 964 3.6 turbo you have!

Danton: I can't quite follow how what you did is much different from just putting an H4 plug on the ends of the current wires. Does this provide a water-tight result? The H4 plug needs a boot that fits the H4 housing as it differs from the H5 housing. If someone could source that, we'd be all set.

Sorry, when I spoke to the guys at AJusa they said it had both end connectors and was a simple plug and play type connection. I am replacing my H5's on the 3.6T with a set of H1's I have from an older 911 and nobody has anything for this. It looks Like I will need to splice into the wiring myself. I think I will use the crimp type connectors to tap into the lines without cutting the harness.

Let me know how it works out. BTW what lights do you use for the H4's. I am getting a very nice GTS coming this week (hopefully) and the H5's are crappy on any model. I don't want to cut the harness so will live with the H5's if I need to, but anything I do must be reversible to stock.

Right on, Anthony! What did you end up getting? Year, colour, etc.?

Anthony: To convert H5 to H4 in 8" size, as on the GTS, you need the full light (minus the plastic shell) from a Euro 928 or some of the 928 specialty houses sell new ones at $250 per side. Says it has the "seal".

http://www.mailordercentral.com/928i...em=5&mitem=105

Mine didn't come with any seals and it seems like a few others here didn't get the seals either. I wonder if the seals from a 7" H4 headlight would work. I'll take a look at my 951 and see. And yes, the plug I ordered from AJ's is just that, a H4 plug. I just think it will look better attaching the plug right to the factory wires then splicing in a H4 plug that brings it's own wires. As far as bulbs I'm going with stock color 80/100's. I'm scared if I get some new "white" bulbs I won't like them.

Don't want to jinx ;) it so I will post when she arrives hopefully this week. I shouldn't have said anything but its very hard to hold in the excitement. I won't have a free day to make the trip for 2 more weeks so trucking is my best option. So for now I just wait and feel like this. :jumper: :jumper: :jumper:

I can't believe the AJ part is only an H4 connector. What good is it without the H5 end?

I appreciate the info. I have lots to learn. :cool: