BigT

Just took delivery of 2019 Cayenne S and had dealer install factory tow package, and need help with trailer connector wiring. We installed a Prodigy P2 controller and 7-pin connector. Normal wiring operates lights/brakes fine.
However, one of the pins in the 7-pin connector is designated to be +12V and is supposed to be hot whenever ignition is on. This wire is used to power battery chargers, etc in the trailer. Problem--no power.
Does anyone know how to activate this pin? The tech has used Piwis to tell car it has a trailer hitch and he claims he can find no other options to activate. There are at least four fuses labelled trailer hitch on the real fuse panel that appear fine.

I have the exact configuration on my 2011 Cayenne S and as I recall we had the same difficulty, only discovered when batter charger in trailer would not work and kept loosing batteries. Dealer (in another state, along time ago) somehow got the power activated after many attempts-he is no longer available so looking for help.

BTW, great first impression of new car.

ramboambo

Hi. I don’t know the answer to your q, but I have a related, simpler question, so I am piggy-backing on yours. In brief, we have a new 2020 Cayenne with a factory installed tow package. The wiring harness receptacle is covered. When I removed the cover, it looked totally unfamiliar, and certainly not like the one on my truck. What am I missing here? What advice does anyone have?

BigT

Ramboambo, I can help you. Porsche ships trailer hitch cars with the wiring harness without any "plug" installed on the end of the harness. There is a nice termination of all the harness wires which plugs easily into a 7_pin connector which is most commonly used. There are different form factor trailer connectors around the world, and in fact there are some other styles available in America. You need to purchase a Pollak 7pin blade connector PK 11-893 from etrailer.com or many Amazon suppliers. Less that $20.
However, from my post above you need to understand that one of the pins-even though wired does not operate. Still investigating real reason.
Good luck.

function12

Usually there is a relay or fuse in the engine compartment that needs to be insert for the battery charging system to work on most vehicles. Not sure if it the same on a Porsche but every truck I have owned. This was ALWAYS a separate step..

ramboambo

Thank you, sir. I have a 7 to 4 converter for my pickup. What you are suggesting is to buy the adapter insert to which the wiring is attached?

Miggytosh

@BigT Did you ever get this figured out? I just got a 2019 Cayenne e-hybrid with the factory tow hitch and the PK 11-893 adapter and I am also not seeing power at the hitch plug. The fusebox diagrams in the manual are super lame too.

Miggytosh

UPDATE: Took mine to the dealer yesterday after I didn’t find power to any of the pins and found out that it needs a load to activate. Luckily I had a neighbor with a 7 pin connector trailer and I was able to connect to that. Worked like a charm first try. I then connected a Curt Echo Bluetooth brake controller and was able to configure without problem.

Side note - Gunter Feldmeier the service manager from Porsche Fremont is the best. He gave me the 411 on the load activation requirements and hasn’t let me down yet over the last two years for any questions I’ve had.

rdboxster

here is what you need: https://www.suncoastparts.com/product/SKU955TPLUG.html

Miggytosh

Here’s the Porsche part numbers. Amazingly my local dealer was cheaper than Suncoast.

the larger box was the 7pin adapter and the the smaller box is an adapter that goes from 7pin to 4pin

BigT

Success ! Just to close my thread out, Miggytosh is correct-The Cayenne Trailer hitch controller (inside left side rear trunk carpet is very smart) The 12V wire in the 7-pin connector is only activated when the controller senses a load on the pin calling for voltage/current. I ran many experiments, and also found a way to connect an appropriate load to the pin for testing if a trailer is not available for testing. See below:

• The key is that I have verified that the +12V wire is NOT activated unless there is a sufficient load (draw) placed on the circuit while the ignition key is turned on or off.
• The vehicle needs to be coded indicating the trailer hitch is installed as described in service bulletin 29/18 dated Jan 10, 2020 as you know.
  • There seems to be no other coding required as I had speculated.
• Through testing, I verified that a very small load (as a single 12v bulb would draw, is insufficient, and likewise a few small trailer led bulbs are insufficient to activate the Porsche trailer controller to recognize that 12 volts is being called for.)
• A larger load seems to cause the Porsche controller to sense the need to activate the 12V line.
  • My trailer has 4 wall mounted LED lights for interior lighting. If all four of those are turned on (they are connected to the circuit in question), the Porsche controller activates the 12V line. Current flow from the Cayenne rose to about .5 A.
  • Alternatively, the 12Volt car battery in the trailer, normally used to power a winch, if connected to the +12V line in the trailer connector, and if it needs charging, places enough draw on the +12V supply line in the Cayenne that it is then activated by the Porsche trailer controller. In my test case, the current flow from the Cayenne to the partially discharged trailer battery rose and stayed at about 3.5 A.
  • Further, the line stays activated and current flows, once begun, even if the ignition switch is turned off. After a few minutes (over 10) the circuit is disconnected. This seems to be similar to the 12v circuits which power the cigarette lighter plugs and must be to prevent complete discharge of the vehicle battery if the vehicle is not running.

• Likewise another way to verify the operation if a trailer is not available is to use a combination of two test tools.
  • First tool----- Curt 58270 7-pin RV blade trailer wiring socket tester. This will test and verify all pins work properly for lights and brakes—but does not draw enough current to activate the +12v line, thus it indicates no voltage..
  • The second tool needed------ Tow-Ready 20142 7-way flat pin plug to plug led lamp-out bypass adapter. This plug is used in conjunction with the above tool, to place a large enough load on the +12 v line to activate the Porsche trailer controller. When this is plugged directly into the cayenne connector, and then the Curt tool above is plugged into this tool, all of its indicating led lights operate correctly and 12 volts are present.

Hope this helps, as i have found many dealers don't understand this and their tech support in Atlanta does not either. Not too many of us really use all the functions of the Cayenne trailer hitch it seems.
Safe towing.
BigT

Miggytosh

Great write, thanks for all the additional testing. Good stuff!

WayneAZ

I have a 2020 Cayenne S and have installed the 7 pin trailer adapter as described earlier in this thread. Surprisingly the adapter can only be installed so the flip door opens to the left or to the right. It cannot be installed so the door opens upwards since the screw holes will not align. The adapter purchased from the Porsche dealer is the Pollak PNA-955-118-93-B 7-pin adapter. Is having the door open to the side going to present any problems? Should I be concerned. Photo shown below.

My second question relates to this comment: "The vehicle needs to be coded indicating the trailer hitch is installed as described in service bulletin 29/18 dated Jan 10, 2020". Is there some way to tell whether this has been completed on my vehicle and if not how do I get this coding completed? Contact the Porsche dealer?

Thanks for all your assistance.

Miggytosh

You shouldn’t have to have anything coded if it was a factory installed hitch. It does need a load before it powers through. Having the outlet sideways also shouldn’t make a difference. I think upside-down would be bad only in that it might be a bit easier to accidentally catch the cover and have it unplug.

WayneAZ

OK! Thanks for responding.

WayneAZ

Well unfortunately this didn't work! I went to UHaul and told them this was the first time I had used the hitch and asked if they would test it out prior to me renting a trailer. They started with a small 4-pin tester and the first sign of trouble was that test failed, no lights. Then they were good enough to let me roll a utility trailer up to the vehicle and attach the 4-pin wiring. We didn't actually connect the trailer to the hitch but I assume that would not affect anything. Again: no lights at all. Then they provided a replacement 4-pin adapter but still no lights.

So unless there is some kind of setting that I am unaware of it seems that it is time to go to the dealer.

Big shout out to UHaul for being so patient and helpful.