I am on the same situation. I am planning to pull a Forest River Mini Lite (4,900 lb dry -10% tong) with a 2017 Audi Q7 on steel springs. I am planning to buy a Curt 45820 sway ball mount to connect a sway control. One issue I have with the Audi ball mount is that de-rates the hitch to 616 lb tong and you have to either weld the sway ball or to put the sway attachment with "some grinding".


By the way, my car is Canadian but I have not being able to find the brake wire as per the youtube video. I am assuming is the same US spec. I am planning to use the Tekonsha RF to avoid messing with the wiring but I think a hard wired connection will be more reliable.

 

You are correct, the Audi made ball mount lists a maximum tongue load of 616 lb. But I do not believe this is the limit for the ball mount, I believe this is the limit of the factory hitch when used with a ball mount of this length. Audi specifies their factory hitch to allow for a (maximum possible) 770 lb tongue load, but this value must be derated to account for the moment arm associated with length of the ball mount. The Curt ball mount is longer than the Audi ball mount so I expect it will have a net allowable tongue load even lower than 616 lb when used on the Q7 factory hitch. I recently purchased the Audi made ball mount (p/n 4L0092770U) online from Jim Ellis Audi. It is extremely beefy - it clearly can support more than 616 lb.!!!
I don't recommend you use the Curt 45820 sway ball mount because it appears the total length is longer than the 6.2" max. allowed length for the Audi factory hitch (measured from the center of the 2" ball to the center of the clevis pin). This is true for virtually all 3rd party ball mounts available on the market....they're typically at least 7.5" long. The Curt ball mount will place a larger moment on the factory hitch, stressing the hitch more than if you use the shorter Audi made ball mount.

I recommend that you:
1) Purchase the Audi made ball mount (p/n 4L0092770U) which is specified for use on late model Q5's and Q7's'; it is within the 6.2" limit.
2) Purchase this Reese sway control mounting bracket from etrailer.com: https://www.etrailer.com/Accessories...e/RP26003.html
You will be able to mount this bracket on the Audi ball mount and then attach your sway control to that. Yes, it might require some grinding or hack saw work, but I don't see another way to keep from violating Audi's 6.2" length requirement for the ball mount.

On wiring a brake controller: Yes, you could use the Tekonsha RF brake controller to avoid messing with wiring. I considered this, but agree a wired system is preferable. I found a ready-made harness on eBay with the Audi plug on one end, Tekonsha plug on the other end, and it is prewired with a relay as recommended in previous service bulletins. I just received the harness yesterday and it looks extremely well made.

Check out the You-Tube video posted by Dihlbe earlier in this thread - he shows exactly how to access the factory harness under the dash only removing 2 screws. I did this and had to look around very carefully inside the dash to finally find the factory harness(!), but it worked exactly like his video showed.

I plan to install my Tekonsha P3 with the eBay harness sometime in the next week or so and will post how it works out.

 

Thanks bud, very useful info.


I did some research and there few things that makes you wonder:
1. Audi Manual says no WDH but the hitch sticker kinda allows it - Ok Manual is from Audi and hitch is from Westfalia - Winner: Audi


2. Audi catalog (online) shows that the ball mount 4LO0092770U is for 2017 q7 but when you deploy the menu for model fitting it shows that is only until 2015 Ugghh.! - winner: the dealership


3. I found lots of stories about the VW Touareg that happens to use the same ball mount. The VW Touareg manual shows that is limited to 616 lb tong weigh..casualty, I don't think so. - Winner: VW


4. Most Touareg owners simply dismissed the 6.2" pin hole-tow ball because basically only an OEM eq. will meet that spec. - Winner: VW


So, the manual shows the dimension of the tow package and the required center to center distance of the tow arm from the ball to the chassis which is 13-15/16".


I calculated the momentum to be 894 ft-lb with 770 lb force. I assumed the 13-15/16" would contain the 6.2" distance so I added 1.3" (equivalent to a 7.5" ball mount) and calculated the force on the new arm (15.24") and it gave me 704 lb. I did couple of more iterations with some other distances and the maximum derating assuming concentrated force at the edge of the tow hitch to be 640 lb. So, with the built-in safety factor I think I won't have any issues towing with a Curt (7.5") ball mount up to 640 lb tong weight.


I am still focused to manage the sway with the sway arm. Your solution look the best compromise but let em know how difficult it may get (or how noisy). My trailer won't be available until end of April...so no practical experience until then.


Regards,


Greg


2017 Q7 3.0 Prestige Sport Pkg, Drv Assis, Tow Pkg

 

Following up on my prior posts, I installed a Tekonsha P3 Brake Controller with the ready-made harness purchased on eBay. See attached photo on where the brake controller is mounted under the dash (sorry, photo is sideways). I can see the display while driving, I can reach the manual braking lever as needed while driving, and it does not interfere with my knee during driving or when getting in and out of the vehicle. The eBay harness was perfect, clicked directly into the Audi factory harness underneath the dashboard and the other end clicked perfectly into the Tekonsha brake controller. I bought the $75 harness with the included relay(recommended) and everything works perfectly. I don't know if I really needed the relay, but everything works! Here is the link to the eBay harness: audi q7 brake controller harness | eBay

I hitched up my camper trailer today (see picture) and took it out for a drive, including on the highway. It tows really well, in some respects better than my prior 2013 Ford F150. The braking worked great and has a lot of adjustment settings available on the Tekonsha. I experienced no sway problems. I don't currently have an anti-sway bar installed. At this point I don't think I will need it, but I can always add it later if I change my mind. Thanks everyone for sharing your input -- You all really helped me get this completed!

 

Hi,


Great pictures by the way. I bought the Tekonsha Prodigy and made my own harness. Unfortunately the Tekonsha did not light up. I tested the brake controller directly from the battery and is working. Then I tested the car own brake controller wiring and I have no power there. Try with the car on and off. I checked the fuse box in the trunk (left side) and all the fuses look all right. I have not tested the brake light (need some wiring from the car battery to do so).


Now, I did all that without plugging a trailer. Do you know if you have to "complete the circuit" with the trailer connected?. Or any other tricks?.


I am about to get the car to the dealership to see if it is an issue with the car wiring.


Thanks in advance...


PS. How was the sagging? do you have steel springs or air suspension?

 

The Audi factory brake controller harness underneath the dash (that comes with the factory towing package) has 4 wires:
1) 12V plus voltage, 2) Ground, 3) Vehicle brake pedal signal, and 4) Trailer brake wire which runs from the harness all the way to the back of the vehicle to the factory 7 pin connector next to the hitch.

When I installed my brake controller, I was able to measure 12V with a multi-meter connected to wires 1 and 2. With no trailer hooked up, I couldn't get any voltage on wires 3 or 4 regardless of whether the car was on or off or brake pedal depressed. So I believe the braking signals (wires 3 and 4) require "completion of the circuit" with a trailer plugged into the hitch connector and/or the brake controller connected.

All I can suggest is that you double check your home-made harness to ensure that each of the 4 wires is connected to the correct corresponding wire on the brake controller. And you should be able to measure 12 volts across wires 1 & 2 on the factory harness.

 

This thread has been a great help. I plan on towing a 4200 lb camping trailer with a 2017 Q7. Since from the thread it appears a sway control hitch is not a good option, I'm wondering if anyone has towed a similar weight trailer with a 2017 Q7 and had any detectable sway. My 2017 Q7 is due to arrive in April, and will have air suspension.

2017 Q7: 3.0T Prestige with Adaptive Chassis Package, Driver Assistance Package, Towing Package, 7 Pin Connector for Towing Hitch

I'll be installing a Tekonsha P3 Electronic Brake Controller

Trailer: 2010 Jayco EXP 19H, twin axle, electric brakes, 3700 lbs dry weight, 4200 lbs loaded.

 

Clarification: Yes, you CAN add sway control to the Audi ball mount by purchasing this Reese sway control mounting bracket from etrailer.com: https://www.etrailer.com/Accessories...e/RP26003.html
You will be able to mount this bracket on the Audi ball mount and then attach a standard friction sway control to that. I don't have exact dimensions, so it MIGHT require a little grinding or trimming with a hacksaw to fit.

What you CAN'T use with the Audi ball mount (to stay within Audi's 6.2" length limit) is a WEIGHT DISTRIBUTION hitch, because there is no way for the spring bars to attach to such a short ball mount.

A weight distribution (W/D) hitch transfers some of the hitch weight from the rear axle to front axle and help level out the vehicle. Without a W/D hitch, you will have some sag in the rear suspension (unless you have the air suspension option). My trailer weighs about 3,600 lb loaded and drops the Audi rear end over an inch, but it tows well and does not sway.

I would prefer to use my W/D hitch (which has built-in sway control as well), but I can't do so without violating Audi's ball mount length limit. But my trailer is well below the towing capacity of the vehicle and has towed well in my test drives so far. I haven't been on the interstate yet on a gusty, windy day -- that will be the real test.

 

I just noticed the link I provided in the prior post no longer works. To find the Reese control bracket I referred to, go to the etrailer.com website and search for RP26003.

 

If you want to read another saga on the brake controller issue to to another forum almost identical to this one AudiWorld.com
Search Q7 trailering issues and go to page 9'and 10.

I went through a bigger nightmare than you guys just to find the plug. Mine was not where it was supposed to be and I found it hidden in the firewall behind the insulation. Real hassle to get it out and had half the dash pulled apart.

I am using a brake controller .... Journey HD by Valley Industries. I did not want to permantly mount it and I have it set up to just plug into the factory socket without any additional wiring harness. Also I was able to snake the factory plug out directly under the steering column. It sits there and is barely visible when the brake controller is not in use.

It is amazing all the hassle everyone has over locating and using this brake controller feature. The audi dealers are useless to help and have no idea what it is.

Audi America is not much better. They originally told me the totally wrong location to go search for the controller plug and wasted many hours of my time looking for it.

Anyway go to forum at AudiWorld.com if you want to see whole story on this and a couple of other issues I have had.