957 Cayenne headlight strange wiring, Halogen + Xenon

[E P]

I am replacing the headlights in my 957 V6 Base cayenne after an accident. I have the set of trashed Halogens that came off the car, and a set of used Xenons (only ones I could find, got them cheap)

 

Now here is where it gets strange...

 

I plugged the Xenons in and fired them up, the main beams come on just fine when the car is OFF. Obviously its throwing codes for side beam lights etc. Which is also weird, since the car did not come equipped with them.

 

So then I turn the car ON, and the Xenons flicker out. I assume the car needs to be coded to xenons so the correct voltage goes to the ballast?

 

The next thing I noticed is that the wiring harness on the car only has 5 pins on it. Yet the halogen light's harness on the light itself has 8 pins! From what I can tell after dissecting one of the old halogen lights, the 3 pins for auto leveling motor should not be getting power.

 

 

Is it possible to order this car with no auto leveling?

Would that mean that the car's harness simply doesn't have it?

Why would the auto leveling motor still be in the headlight?

 

Very confusing... I just want working headlights at this point tbh.

 

 

 

Edited April 2, 2022 by E P

[JFP in PA]

Welcome to RennTech 

 

From the factory, all Xenon equipped vehicles had auto leveling due to legal requirements in some countries, and as such had an additional control module for the leveling, leveling sensors on the chassis, and different wiring. And in the factory Xenon's, the leveling motor is in the headlight assembly, but is controlled by the external control module.

[E P]

Thanks! I lost my old account some time ago, but I been lurkin since lol.

 

The leveling function is definitely not wired into my harness, but it is independent of the ballast/igniter/bulb of the Xenon HID system. In other words, even though the auto leveling isn't there, it shouldn't stop the lights from functioning. Upon dissecting the headlights it is clear that only 2 wires are required to fire the ballast.

 

I also have a few theories about the situation of "engine OFF = Xenons working, engine ON = Flickering out"

 

1. Voltage to the ballast. It could be that the ~12V supplied from the battery is within the correct range for the ballast to fire when the car is off. HOWEVER, when the engine is on, the alternator provides closer 13.6-14V. This could be outside the operating range of the ballast to function correctly. I find this unlikely but its possible I suppose.

 

2. CANBUS. Is it possible that the canbus system is seeing incorrect return from the HID lights because they run lower output wattage than the halogen's 55W? Could the control module for the headlights be turning them off since it thinks there is an issue? 

 

I welcome any other ideas on this. It seems simple, but there is something I'm not seeing.

 

 

[JFP in PA]

Unfortunately, the Cayenne is not like the Boxster or 996 when it comes to retrofitting Xenon headlights; you simply cannot "plug and play" Xenon's for halogen lights as the wiring harness is different, the control module needs to be installed and requires coding, as does the CAN Bus system in order for everything to function. It can be done, but it is a lot of work and requires access to a PIWIS, and those that have done it seem to question the value of what you get for the all the work and expense.  This may also be why the factory never offered retrofit kits like they did for the other vehicles.

 

It seems that most people interested in this project go to aftermarket LED kits to get around the factory retrofit issues. 

[E P]

I guess that's what happens with all these VW parts... 

 

Sigh, I miss my 911s

[JFP in PA]

Porsche learned a bit of a hard lesson from the 986/996 cars; to save costs, all those cars were wired and even equipped for options like the on-board computer and Litronic headlights, even if they were not installed when they left the factory, apparently to save costs and in expectation that both they and the dealers would be able to cash in on "post-delivery" installations of these pricey options. But what ended up happening was both the independent shops and the DIY market taking advantage of the ability to do these upgrades without the dealers because the dealers were trying to charge full boat option prices to do things like activate the OBC system, which takes about 15 seconds to do.  The later cars took a different pathway and required changing out sections of the wiring harness and adding electronics that require appropriate coding into the car's communications network to function properly, which cut out a large portion of the DIY and independents simply because many lack the required parts accessibility and coding ability. 

[E P]

I think the plug and play options for the 996 that Porsche offers these days are pretty cool. If I still had my 996 I would certainly pay the premium for the newer CarPlay updated head units they are selling. I wish more OEMs would do this. My BMW is desperate need of a headunit upgrade, but all the aftermarket stuff is painfully ugly and does not at all match the matte black minimalist style of the BMW radios.