After reading all that was offered here on the trailer hitch install I finally tackled the project. I was "grasshopper" to my friend and fellow DE'er Tom, a Porsche master tech who did most of the install. The install went flawlessly and the module was flashed to "US" mode. I was well prepared for the "!" due to my LED trailer lights as I read all that was offered here. Thanx to all that posted. So far, no sweat as all the lights worked. The trip was fantastic pulling wise. the CS pulled better than my 04 Silverado Crew due to the 6 spd tranny. It was very smooth even up the larger hills. Ok , here are the two lighting issues maybe someone has had and can clear up for me.

1- when there are no lights on as in daytime driving, the trailer brake/turn lights flash dim and quick. the brake lights and turn signals work correctly but they are working around the steady fast flashing, Im thinking grounding issues but Im not the best at electrical so I would like some advice.

2- This one I found while unloading at home after the trip. Rig parked. no lights on at all on the CS but the rear tail lights on the trailer flash every 3 seconds or so. i thought it is the alarm but it is not the same pattern as the LED alarm light in the door. this one has me stumped. the rig is totally off. all doors and hatch closed. parked, but tail lights still flashing every 3 seconds. Does any one know why?

Thanx,
scott

 

Here I am, laying here peacefully in my casket, enjoying some much deserved/needed rest and what am I woken up for?......another fr!gg!n tra!ler l!ight!ing quest!ion....
Cayenne and Tra!ler L!ght!ing? Who would have thought?

Fine, since I'm awake now.......

Your towbar control un!t (1D6) equ!pped with the latest !n PAG/VAG !n-vehicle bulb d!agnostic F/W has detected a light!ng load fault (re: LED tra!ler l!ght!ng connected to the 7pin Pollack connector) and w!ll s!gnal sa!d error by rap!d low duty cycle puls!ng on the l!ght!ng l!nes. Get yourself an osc!lloscope with clamp on current probe and you'll see exactly what's happen!ng.

The 3.2 second l!ght pulse when parked !s the duty cycle of the aforement!oned 1D6 !n-veh!cle bulb d!agnost!c algor!thm. Every ~ 3.2 seconds, the system w!ll send a br!ef pulse of current (sw!tched voltage !f you prefer) out to the l!ghts and measure the current drawn (or !nfer res!stance !f you prefer)....of course the stup!d th!ng !s that you can NOT know !in advance how many and/or what type of tra!ler l!ghts have been connected to the 7 p!n Pollack, so the system !s des!gned to fa!l !n th!s manner....yes, PAG electr!cal eng!neers are not the br!ghtest bulbs on the Chr!stmas trees. You can see th!s with LED's more than !ncandescents, s!nce they have a much shorter t!me constant than large f!lament !ncandescent l!ghts.

Of course there's noth!ng you, or PAG, or PCNA or Peter the Great can/w!ll do about !t, so you're stuck with !t. Enjoy.

Love,
Larry

 

I heard you were on sabatical... Anyway, I saw this post and thought you would miss a good one!! Home, and a not a moment too soon.

BTW, this was on the "other site" and thought you might find it interesting.

http://store.uhaul.com/product_detail.aspx?id=4089

Who would have thought U-Haul would beat Porsche for the opportunity to make a few more bucks!

 

Cayenne forum member 'Wingless' pointed out that device a while back.

I'm just looking forward to more quality casket time with no more ! posts.
BTW, no, I'm not dead yet.

 

Ahhh, Larry, !t !s so good to see you al!ve and well and amongst fr!ends !n Cayenne tra!ler l!ght!ng n!rvana! !'d offer to come v!s!t you !n the padded cell but then !'d have to adm!t that ! bought another Cayenne and your meds would have to be s!gn!f!cantly !ncreased... hugs, your fr!endly meds allocater

 

Yes it's nice to see Larry back amongst us- looked at that Uhaul thing for the hell of it as I have regular lights and notice it's a 4 plug not 7 pin system so it wouldn't work without an adapter and wouldn't seem to work with trailer brakes, etc...

 

Boy - this horse must be GLUE!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Welcome to the world of "Porsche Towing" - Larry tells me that damn "!" will burn out but I'm still waiting...

 

It won't work as a plug in but you can easily wire it into the trailer after the 7 pole connector. That way the trailer looks like incandescent lamps to whatever it's plugged into.

 

It's amazing that Uhaul makes a fix for something that doesn't even exist.... according to Porsche...attention, cue Larry...

 

I didn't mean to disturb the dead. I can now tow in peace. Thanx for the explanation, Larry. You can now return you to your perpetual slumber.
Scott

 

The reality is that Porsche never said it didn't exist, they said it's working as designed. It's a function of the tow modules design to check current flow to detect burnt out bulbs. Many other light controllers use this technology and whenever this technology is encountered you have to add load equalizers when you use LED lights. This is nothing new or earth shaking (ask any BMW motorcycle rider who has converted to LED tail lights).

Just because American truck makers don't have this feature doesn't make them superior (as has been touted by many here). It just means they don't care if anything is plugged in or not.

It's also not surprising that Porsche doesn't supply a "fix" considering it would invalidate their initial design criteria. The part that is stupid, IMHO, is that Porsche doesn't produce a dealer tech note to explain this so dealers can correctly diagnose customer complaints. To me it would seem like proper customer service to have the dealerships be able to identify the problem and communicate it to the customer. I wouldn't have any problem if the dealer told me that if I want to run LED's I need to wire in a load balancer. The fact that dealers give you a blank stare or tell you that it's YOUR problem is what's unacceptable.

 

OH I remember the poor dealer spending days re grounding and generally trying to fabricate a solution to what PCNA said was not possible. They did get it going but only after my LED's went and regular lights were installed on the trailer.

Still get ! tho, but I dont care they actually stay on when they are supposed to and flash when ordered. I bet the dealer would have loved that Uhaul box.

 

Hello again, Larry here.....
Hmmmn, Cayenne trailer lights again . FWIW and not that it matters, here we go again.
OK class, pay attention.....

PAG made a fundamental engineering design mistake when extending in vechicle bulb diagnostics to the 7pin Pollack, PERIOD. This is not subject to discussion nor negotiation, trust me....been there, done that.

Why, you ask? Simple.

In the vehicle, the lighting type/load is clearly known to the designers, so the response to the bulb diagnostic pulse is therefore known. (We'll skip the part about defective bulb connectors throwing false warnings....we've covered that in the forum before)

With a trailer, the designers can NOT know a priori exactly what the bulb type and/or number are. Many tenets of physics involved here (Heisenberg, Einstein, all the greats).....so what to do?
Two choices:
1. Simply do NOT extend vehicle bulb diagnostics to the 7pin Pollack
or the incorrect decision
2. Extend vehicle bulb diagnostics to the 7 pin Pollack and program 1D6 against a target for the ASSUMED/FIXED TRAILER LIGHTING LOAD.

For those of you who've been with us for a while, they went with #2, assuming a 4-6 incandescent open trailer lighting model.
Too many incandescents.....!
Any number of LED's...........!

Now, for those of you who fancy yourselves electrical types, the answer for LED lights is obvious......put a resistor (or load equalizer if you work in marketing) in parallel with the LED lighting load, thus raising the load up to a level approximating the assumed/nominal PAG trailer lighting load.
And guess what happens.......drum roll please.......

NO "!"

But wait, put the champagne down......2 problems.
1. If the resistors loads are on the vehicle side of the 7 pin Pollack, your secondary directional towing indicators " <1>" on the dashboard will be illuminated all the time, as the 1D6 thinks there is a trailer (load) connected and signal, via CAN, the Cayenne this 'fact'.
2. If the resistor loads are on the trailer side of the 7 pin Pollack, then you can blow out a trailer light...or two...or three....or all of them, and the 1D6 will not say a peep; it sees the load which is now independent of the trailer lights.

Can you tell I've been thru this before?
Can you tell that somebody (no names) may have had a bit of fun with PCNA/PAG over this design?
Can you tell that a German PAG electrical engineer ended up screaming into a phone during a debug session......
Can you tell that somebody may have enjoyed this whole thing? No names, please.

From PCNA/PAG's perspective, since "!" Check Trailer Lights isn't covered in the owner's documentation, then how could it be malfunctioning, if it's operation is never disclosed/detailed?
Why is the recommended/assumed electrical trailer lighting load/type not outlined in the owner's documentation?
Why are the PCNA technicians not given any information to troubleshoot this issue?
Inquiring minds want to know......


For those who are truly inquisitive, please refer to our resident 'Legal Beagle'....aka 'rome'......I'm sure there MIGHT be some papers filed in a US district court describing something very similar to what has been described above.

Class dismissed


P.S. From this point forward, it is now considered Cayenne Forum "Man Law" that the words "trailer lighting" are forbidden in this forum.
Failure to abide by this "Man Law" will result in 'ltc' being taken off his happy personality meds and given a day pass from the vacation villa to pay a visit to the offender.
Thank you for your attention....that is all.

Hugs and Kisses,
Larry

 

 

Actually problem number 2 is no problem at all since that's the mode that 99% of all the other tow vehicles operate in...............

Now, back to your regularly scheduled programming