Well, Bozo III has spent the day reading wiring diagrams! Here's what I have discovered!

I'm getting close, and the good thing is that it doesn't look like it is impossible to do! More to come!

Toby (aka Bozo III)

 

Working to solve the "mystery" of the Headlight Beam Adjustment motor found in the USA halogen assembly. When you look at the assembly, it is the same motor as found in the Bi-Xenon assembly. Interestingly, the halogen motor has some sort of additional controller added on AND fewer wires than the Bi-Xenon assembly. So, tonight's science project is trying to discover how the HBA is wired in the halogen installation and see if it can perhaps facilitate a similar function in the Bi-Xenon world!

First off, a careful (and I DO mean careful) study of the wiring diagrams shows that the HBA is wired into a part denoted as "Dimmer HVAC". I haven't figured out what HVAC stands for yet, but here's what's happening.

You'll recall from earlier lessons that PINs 2 and 3 in the halogen assembly are leads that are wired to the HBA motor while PIN 4 is a Ground for the HBA. When you trace the wiring, you find that PIN 2 on each light (left and right) is bridged and the same holds true for PIN 3. PIN 2 is labeled as HVAC, while PIN 3 is labeled HVAC Sensor. PIN 4 (labeled Terminal 31) is a Ground that is also bridged across both lights, BUT ALSO appears to be tied in to the On-Board Computer Network Control Unit at Position J3. PIN 2 is bridged into the Left Fuse Box at Fuse F54, so this must be a power source for the HBA. So, that leaves PIN3 (labeled Sensor HVAC).....

Where does this little jewel tie in? Interestingly, it ties into something called the Dimmer HVAC. This Dimmer HVAC device seems to govern or regulate voltage for the low beams and parking lights, BUT....... THIS IS NOT TERRIBLY CLEAR and thus my first question to the crowd of experts....

What in the world is the "Dimmer HVAC referenced on Diagram 1 at coordinates D11 and D16???????

I'm wondering if this wiring can substitute for the HVAC sensors on the left front and left rear axles of steel springed, Bi-Xenon equipped cars??? Both the HVAC Dimmer (halogen) and HVAC Sensor get their power from Fuse F54 and there are no noted connections into the Computer Network Control Unit. Anyone care to hazard a guess?


Observation Number TWO for this evening's diatribe.....

Once I solve Problem Number One above, I only need to figure out how to secure a K lead and Error Indicator lead on the car. The K Lead is wired into the Diagnosis Socket (Diagram 23, Location D18), while the Error Indicator is wired to Terminal A9 of the On-Board Computer Network Control Unit (Signal LWR Error), Diagram 1, location D7. Anyone care to offer some suggestions on where I might be able to tie into either of these?


Finally, the cornering lights.
When you trace them down, it appears that the corner sensitive lights can be enabled by plugging in Fuse F21 (Diagram 1, Location D9). Can someone verify my thinking on this?



OK, ENOUGH ALREADY! I've stared at these wiring diagrams (monochrome, mind you... NOT color) all night long. You guys have sucked whatever miniscule knowledge I might have gained right out of me.

I'm going to bed!

 

OK Boys and Girls....... Bozo III back again with another update.

I have stared at these DAMN wiring diagrams for two nights in a row trying to track down just exactly what the Dimmer HVAC part is. I think I now know...... and I'm not sure I believe it!

If you'll recall, the halogen assembly has a Headlight Beam Adjuster almost identical to the Bi-Xenon assembly. However, the non-PASM vehicles with halogen lights do NOT have any level control sensors installed and these sensors on the left front/rear wheels are the suppliers of input to Bi-Xenon HBAs. That said, the input for the halogen HBA is something called a Dimmer HVAC. I traced the wires three separate times, and each time came to the same conclusion...... the Dimmer HVAC switch (drum roll please) appears to be the.....

Instrument Cluster Lighting Rheostat!!!!!

Do not ask me how this can possibly work because I cannot prove it with my car. I think that the HBA is essentially INOP on halogen cars!

So, I'm not quite sure where to go with this. Gert or wingless, I need your input here. Can you guys check the wiring diagrams and validate this for me? Specifically, I'm focused on Charts 1 (Control Unit wiring layout) and 1A (halogen headlights). Look for wire 58b - it's a gray wire and is plugged into Terminal C1 on the Control Unit. Terminals J1-J3 also deal with 58b. Please let me know what you think.

THIS one is going to make me go bald!

 

Toby

There is another rheostat on xenon fitted cars, a leveling adjustment. The car I tested was a non Air with lights, I remember playing with it.

 

Mike,

The sensors that provide compression signals to the Xenon lights front and rear on non-PASM cars are 955 341 075 10 (front left wheel Self-Levelling Sensor with Linkage) and 955 331 077 10 (lefr rear wheel Self-Levelling Sensor with Linkage). I have not found any other references to a rheostat in the Bi-Xenon cars.

I'll check again, but I can't recall seeing any other adjustment capabilities on Bi-Xenon, non-PASM cars. Thanks.

TBP

 

Mike,

Did the car you played around with have a switch like this one in the diagram below??



If so, then I may be making progress. Also, was this on a Xenon car without air suspension? Any other Cayenne owners have a non-air suspension car with Bi-Xenon lights? If so, can you confirm or deny the presence of this rheostat? PET lists two parts:

955 613 230 00 - Potentiometer for manual leveling
955 612 231 00 - Potentiometer for dynamic leveling

If the non-air cars have this adjuster, then perhaps I can order the part of get the adjustments I need for headlight leveling.

It's amazing what you find while combing through the Service Information Technik manual!

Thanks in advance to any of you who can help with information on this.

Toby

 

I've been following the installments of this saga in the hopes that this story will eventually have a happy ending. It does look like you have something here although I will not be much help in confirming it. The latest Car Talk column from the newspaper discusses xenon headlights and the manual height adjustment some vehicles have. Mine adjust automatically, as do the ones on my wife's X-5, but they both have auto leveling air suspensions.

BTW, will this story be available later in paperback?

 

Yes that was it, in fact I saw it yesterday, the demostrator at my dealer

 

Sorry I missed the second Q, yes it is non-air

 

hmmm chasing the publishing model Gary ? remember the copyright issues.

:-)

 

Gary,

Yes, I'm considering publishing offers as we type.

I just got back from a little excursion up to Boardwalk Porsche in Plano. They have a number of Cayennes with Bi-Xenon lights installed. Interestingly, NONE had the manual adjustment and ALL were non-air suspension cars. I wonder if Porsche made a change from MY03 to MY04? Mike, is the demonstrator you saw an 03 or o4 model year?

TBP

And yes, signed copies will be available to those desiring them. I don't think I'll be as popular as Adrian, but hey, you never know.

 

Oh, I forgot to mention that I just finished putting on the roof rails and roof strips. I thought the roof rails might turn into a new version of the previous Tobyquest, the Cardan Shaft Shipmentgate. When I opened the first box I had ordered, there was a bike rack inside. The dealer apologized and said he would order a replacement right away. He later called and said he got the replacement rails in but they were freight damaged and all rails were now on backorder from Porsche. He did try some other dealers, found me a pair and delivered them to my office in exchange for the bike rack. I did notice a shipping label on the box indicating that the rails had come from Park Place Porsche in Dallas.

 

DIE YOU DIRTY DOG!!!

 

I posted a wiring proposal as well as a mea culpa for some previous documentation errors. If anyone would care to review my proposal for wiring and offer suggestions or counters, I would really appreciate it.

Toby, um I mean, Bozo III

 

Gary,

Do I see a "gingerbread, non-functional adornment" (your own words) on your Cayenne? Shame on you!!

Oh, and by the way, now I am finally beginning to understand where all this boxes full of parts and "Park Place Porsche" written on them were destined for. The Porsche parts trucks stops by about once a week asking for "Dallas Texas" and I usually tell him that I have no clue where that is but that he should drop the parts in my garage. Did I do something wrong?



Toby,

I'd have a suggestion for a next project: Homelink. I'd be highly interested in what you will find out about adding this feature.
Just make sure that Porsche doesn't sue you for reverse-engineering the complete car.
Seriously, good luck with your Bi-Xenons.

Cherio,
The Swiss Dirty Dog