Toby Pennycuff

Does anyone have access to the factory wiring diagrams for the Model Year 2004 Cayenne S? I am trying to see if I can complete my latest science project...

Upgrading Halogen Headlights to Bi-Xenon Headlights

Specifically, I want to understand the detailed wiring and connector pin-outs for part numbers 955 631 239 10 (Bi-Xenon headlamp harness) and 955 631 239 00 (Halogen headlamp harness). It's my belief that the upgrade from Halogen to Bi-Xenon is pretty straightforward. There are however, a couple of key elements - the proper wiring to insure that the light signal gets to the ballast to fire up the Xenon lamp, and insuring that the Xenon control unit is not a physical control unit but one or more mappings in the CAN drive modules.

So, if anyone has access to the wiring diagrams, please drop me a PM or an email.

I'll share any progress on this front.

Toby

SFernando

Asked the dealer service rep about the conversion from halogen to xenon. He looked at me like I was the man in the moon but promised to get back to me. No word so far...

Toby Pennycuff

Well, the good news so far is that I have dissected a Cayenne Bi-Xenon assembly and identified all of the wiring connections and pins among the assembly connector, the ballast, the beam adjustment motor and the various lights. I also have two headlamp harnesses on order - one from a halogen setup and one from a Bi-Xenon setup so I can compare the two for wiring differences. Finally, I did the same discovery routine on the halogen assembly. At least now, I know where all the wires go on both assembly types.

From past personal experience with an 03 ML350, I was able to replace the factory MB halogen projectors with factory Bi-Xenon projector headlights. The trick was the wiring harness between the vehicle and the headlight assembly. Once you knew what wires did what, it was pretty straightforward to get the switch done. With the Bi-Xenons installed, I went down to my MB dealer and they enabled the Xenons with their Star computer (the MB version of the PST2) and voila! I had factory Bi-Xenon lights! Granted, I did not have the leveling capability or the washer capability, but those were nice to haves for me.

Since the Cayenne includes a leveling function for both halogens and Bi-Xenons, I'm betting that the only thing I won't have compared to a factory Bi-Xenon setup is the headlight washer capability. Frankly, who cares?

So, I bought two used Bi-Xenon assemblies on eBay and should have them later next week. I'm making progress and both Loren (renntech.org) and Gert are helping me along the way too. It should be an interesting science project. Once I get it to work, I will publish what it takes and part numbers, etc......

This is such a desirable option that I'm surprised Porsche has not developed this upgrade for the Cayenne like they have for the 911 and 986!

Brent 89-GT

What about controlling the integrated cornering lamps? They supposedly read steering angle and illuminate into the corner. This is another feature besides the washers that I would guess is tough to make work in a conversion.

Toby Pennycuff

Brent,

The cornering lamp in the Bi-Xenon assembly is a separate light (one of six inside the assembly). Fortunately, it is not controlled by the autolevel signals so there may acutally be a signal that feeds it from the front sub-part electrical harness (955 612 913 00 and 955 612 914 00).

It's hard to know right now because PET shows different part numbers for these harnesses when you have option I8BR (halogen lights, I think) versus I8BC/I8BZ/I8JD (I8JD is referenced in PET as the Model code for the Bi-Xenon assembly). From what I can tell so far (using PET diagrams, specifically Illustration 902-10), this sub-harness is only for front lighting including the headlight, side marker and lower parking light. That may make things a little easier.

Better news is that both the halogen and Bi-Xenon assemblies use a headlight aiming motor to control positioning of the light beam (955 624 209 10 for the Bi-Xenon assembly and 955 624 209 00 for the halogen assembly). There is a difference in the input wiring to the motors (3 leads in the xenon versus two in the halogen) and I'm trying to figure that out.

The overall mapping of leads and grounds is pretty straightforward and I think I can make this work without too much trouble. I still don't have a solid feel for whether a physical xenon control unit exists or if it is merely software mappings that live in the CAN-bus and control units that form the electrical heart of the Cayenne. Between the control unit issue and the autolevel wiring, those seem to be the biggest issues.

As you can tell, I'm on the hunt for this. I acquired a broken Bi-Xenon unit off of eBay and used it as a sacrifical lamb for my dissections to understand the existing wiring schematics. Since I (obviously) have halogens on my car, I was able to go through the wiring for that unit as well. I have the headlight harnesses on order and should be able to look at them this week and determine differences. I may still have to work backwards into the sub-harness, but I hope not.

As I noted to Loren over on Renntech.org, this may turn out to be a worthwhile science project. If trends hold, my bet is that many of the V6 Cayennes as well as many Cayenne S models are being ordered with halogen lighting. That leads me to an initial conclusion that there may be some kind of market for a Bi-Xenon upgrade if it's reasonably straightforward.

Stay tuned for further updates!

TBP

Brent 89-GT

I'm just glad I ordered my Cayenne with the Xenons for the factory

Periokid

If this wiring diagram is available, I'd love to see how the side marker lights are wired and if there is a difference in wiring between USA and Euro models. I still want that light to flash!!

Toby Pennycuff

You could always splice into the turn signal lead and use it to drive the light rather than the side marker light.

On the Bi-Xenon lights, I believe that the turn signal lead is on PIN 2 of the connector. PIN 10 is a combined ground for Cornering/Parking/Signal lights. The PINs are numbered (looking at the back of the connector):

1 2 3 4 5 6
12 11 10 9 8 7


On the halogen light assembly, PIN 9 is the turn light lead and PIN 10 is a combination ground for Low/High/Turn.

From what I can tell, there is a completely separate lead/ground pair for the side marker lights are installed from the factory.

YMMV!

Periokid

If I was going to splice, I would want a functional solution like this 996 mod.

http://wa4ekg.home.att.net/996mods/sidemarkermod.html

That way, the light would illuminate solid with the headlights on and flash when the signal is on.
How are the pin # determined? If you pull the headlight out the plug is in the back facing forward. Do I count the pin # looking right at it?

Toby Pennycuff

When you look at the rear of the light assembly, the connector is plainly visible. If you consider the upper left side as position 1, then the top row goes left to right in ascending order (1-6). The bottom row goes descending from 12-7 read left to right.

bjwebster

I think that it would be great to get it to blink, but what scares me about splicing, is the light out indicators, etc.

http://danielsternlighting.com/tech/...rkerflash.html

Periokid

bj,

Thanks for the link. It is helping me understand the way the circuit works.

I assume it may only effect the bulb sensor in that particular circuit.

I may attempt this project to see if it will function correctly.

Toby Pennycuff

For those of you who peruse the 993 board here on Rennlist, you will see some pretty humorous posts about "Bozo" and "Bozo Jr." Well, I think I am coming close to laying claim to the title of "Bozo III"!

I think I may have solved the mystery of the "Xenon Control Unit" depicted on the CAN-Bus ring diagram in the Technik manual. After careful reading of the PET parts list again, the Ignition Control Unit (part number 955 631 239 20), must be the afore-mentioned control unit.

Here's my rationale.... When dissecting the wiring harness (thankfully I have a donor assembly that I can tear up!), I found that there are four leads and one ground into the Ignition Control Unit. One lead and the ground are for the xenon bulb itself, while the remaining three leads appear to be the steering signals for the autolevel motor. For the life of my I could not figure out why the ballast would serve as a pass-through for these adjuster leads. (Can you see where this is going?) To make matters worse, I took the harness plug apart so I could see how the wires were bridged in the connector. Strangely, there was no bridging going on. "Hmmmmm, I wonder if those wires are control wires", Bozo III said to himself. "Wait a minute... CONTROL WIRES!" DUH!

Clearly, the Ignition Control Unit (operative words there folks...... control unit) is a combination piece of equipment - ballast and controller! I think that the three leads provide signals on how much to move the adjustable light assembly. (And THAT is another story!)

OK kids, to summarize..... Bozo III has found that 1) you CAN, in fact, combine multiple units into a single assembly! (Wow! What a concept!), 2) When you read things like "Ignition Control Unit" in parts lists for Cayennes, MAKE THE CONNECTION (instead of wondering where in the HELL is that damn control unit on the CAN-Bus!) and 3) Do NOT assume that a ballast would EVER serve as a pass-through device.



Now, all that said, I am getting closer to success on this project. My two new Bi-Xenon assemblies arrived today. I still have to secure two D1S bulbs and harnesses and those miraculous ignition control units (about $800 total! )

And that's how I spent my Friday evening, teacher!

bjwebster

Wow, Quite The Hide And Go Seek!

The Bi-Xenon Retrofit On My ML320 Was So Simple, LOL, This Time, I Got Them Factory Fitted, Good thing I Guess!

GM Austin

That's a pretty funny story Toby. Sounds like one of my projects.

I have finally ordered the roof rails and in fact thought I had picked them up yesterday. When I got home and opened the box, it was actually a bike carrier! I called the dealer and they apologized and said they would have the correct part by Monday and would bring it to my office to make the exchange. I hope this doesn't develop into the tobyshaft syndrome.