Toby Pennycuff

Well, I got my Cayenne back today from Park Place with my Porsche Towing System hitch installed. Cost of the total package was about $1000!

While the service rep was showing me the work, he pointed out the hitch and the ball assembly and the electrical adapters for the lights (a $30 part from Ford versus the $100+ Porsche part!) on the trailer......

AND THEN HE SHOWED ME WHERE THE TOWING CONTROL UNIT IS!!!!!!

No wonder this silly thing costs so much! Not only does it have reinforced pieces for attachment to the bumper/frame, it has an electronic control module that is plugged into the CAN-bus (CAN Convenience ring). It is officially designated Control Unit Number 20 - Trailer control module, and it lives just in front of the CD Changer on the right rear wall. (GM Austin check page 9.9 in your Technik Manual) I have the dealer off trying to tell me exactly what this module does. I would assume that it "speaks" to the PASM (if you have it ) and other modules on the CAN drive unit. Will find out and post more details.

At any rate, I have wondered why a silly piece of steel would cost so much. Now I know...... it's not the steel STUPID! It's the control unit!

jhunt@huntinter

That silly piece of steel probably cost Porsche more than the over engineered silicon and machine code.

GM Austin

The labor to install them is the real cost.

Thanks Toby! That book is great isn't it? (part #PNA488910 at your dealer). The page that Toby refers to is a network layout table showing the unit number for each device on the network; 46 devices numbered 1-41 and A-E.

mudman2

Toby

did they put a new skirt on or cut the existing one?

Toby Pennycuff

They cut the existing one. From what I can gather, the various parts are templated as they are manufactured to facilitate proper placement after the fact. I saw that on my skid plate installation and looked at a rear skirt that was off the vehicle and saw the same outlines.

Toby

oscarb57

<<AND THEN HE SHOWED ME WHERE THE TOWING CONTROL UNIT IS!!!!>>

But that's not a brake controller. So what does it do, exactly?

Toby Pennycuff

I have not yet discovered this particular control unit's purpose in life. Hopefully, I can get some time tomorrow so I can talk with my service guy and get the details.

Film at 11 folks.

jhunt@huntinter

There's nothing inside. It's just there to seperate you from your money :-O

WCS

So basically if I do not have air & PASM, I'd be equally well off with a regular aftermarket hitch, right?

Torags

The controller controls electric brakes on the trailer.

Lightweight trailers do not need brakes. Middleweight trailers usually use surge brakes (that don't require electric brakes). Heavy duty trailers may have the electric brakes, which feather better & back up hill better.

Careful with your tongue weight on the trailer load you choose - that is a contensious issue.

Toby Pennycuff

Absolutely! I need to go back and re-read your posts on the brake controller too. Didn't you wind up buying one from a trailer store??

TBP

Torags

No, I have surge brakes on my boat trailer (only 'bout 6,000lb +/-).

I have no controller and I get alerts in my gauge (S doesn't see brakes & considers it a failure) when brakes are applied.

Fabianrou

On my 04 Cayenne today I got a horrible grounding noise coming out of the speakers and it all happened after I towed my jetski not realizing that the wiring on the trailer was bad. This is the first time I tow it since I bought the car a month ago. The noise came on right as I try to plug in the DURAMETRIC Software cable (also for the first time) to check for fault codes. I was however able to check the faults and sure enough the car knows that something was wrong with the trailer wiring and it threw a whole bunch of codes for it. I cleared them but the grounding noise is terrible and still there. The kind that you get when you rev up the rpm's. It is very loud and I have no idea what is causing it. Any thoughts? Exactly where is the towing module and is there a way to check it?

seankrider

Towing controller is above right rear wheel well. Pretty hard to get to as I recall - lots of panels have to come off...