Good to see this progress. I've spent too many grey cells on this and stalled out numerous times. I have a 2017 Q7 Prestige with air suspension and factory hitch wiring. - First problem: My hitch tester showed no power so I took it to the dealer. They agreed it had a problem so kept it for 2 days, ordered a new tow controller then kept it for 3 more days. Final conclusion: it had no problem other than that the '17 does not output voltage unless it sees a resistive load. Their tester (and mine) incorrectly said it failed. They finally figured this out and got a new tester with resistors. They also tested it at a boat dealer on a boat trailer. Hmm...does this mean a trailer with LED lights will have a problem?
- Beware of pre 2017 documentation. The regional Audi tech specialist sent me a TSB for Q7's that incorrectly shows the tow controller on the RIGHT rear whereas it is really on the LEFT rear.
- I did manage to get the dash apart by trialand error and found the connector. There are three screws I had to remove--one of them behind the left side fuse panel.
- I bought the ebay harness with relay and a Tekonsha Prodigy P3 and hope to install it soon--maybe this weekend. I will be looking to see if you guys are able to make this work before I get to it.

 

-I measured no voltage on some of my 2017 Prestige Q7 trailer harness leads under the dashboard, but it turned out everything worked fine once it was all hooked up with actual trailer electrical loads on the system.
-My trailer has LED lights, and I have had no problems -- everything works as it should.
-Suggest you review the prior posts in this thread. The solution is all there.
-By the way, I relocated my Tekonsha Prodigy Brake Controller to the far left side under my dashboard. It turned out my original mounting location was very close to my right knee and could have been dangerous in the event of an accident. Moving it to the far left side (above the hood release) is better -- surprisingly it doesn't interfere with getting in or out of the vehicle and has much more clearance away from my knee while driving.

 

Hey Snowbird22, I understand I'm a little late to the party on this thread, but I just got my 2017 Audi Q7 Prestige w/ Air Suspension and stumbled upon this thread while trying to get everything ready for our trailer (Kodiak 253RBSL). So far it has been really helpful on the brake controller/harness front!

I had some questions about your comments on the tongue weight and derating due to length.

My first question is about this 6.2" length limit you mentioned -- Reading over the 2017 Q7 Manual's towing section, I could not find any mention of such a length limit.

Can you tell me where you got this information from?

Everything that I have read online so far indicates that the maximum tongue weight specification of a tow vehicle is usually based upon a standard tow ball length, usually 11".

Of course, if specified otherwise by the OEM there would be an exception, but I'm just struggling to find any official docs that state this (so far this forum thread is the only place I have seen it, aside from literature that refers to VW Touareg).

Mainly I was looking at info on this link: Extended Hitch Calc

It seems a little odd to me that possibly the shortest ball mount in existence causes you to lose 20% of your tongue weight capacity, but I guess stranger things have happened?

Any help or insight you have would be appreciated

cheers!

 

I've updated my interpretation of the 616 lb. tongue weight limit listed with the very short Audi made ball mount. As I previously stated, this limit makes no sense because the ball mount is extremely beefy - as beefy as any ball mount I have ever seen, even for 10,000 lb travel trailers. I did some online research and learned the Audi made ball mount could be used on multiple Audi and VW models, including the Touareg. Some older Touareg's had a 7,700 lb towing capacity and a 616 lb. tongue capacity! So my guess is Audi simply lists the lowest rated tongue capacity of their vehicles with their ball mount, regardless of what vehicle it is used with.....which makes no sense.

Regarding the 6.2" length limit of the 2017 Q7.....this is listed on stickers on the side of the factory installed hitch receiver. See attached photos. Interestingly, it doesn't say it is a load limit, it says "risk of loss of vehicle control".....so maybe Audi is concerned about the hitch length vs. the vehicle wheelbase for overall towing stability. Regardless, the Audi Q7 manual says to "never" use a weight distribution hitch (which is always longer than 6.2") because "the hitch attachment can fail, causing the trailer to tear loose from the vehicle". Okay, message received, I'm not going there. This is really frustrating, because it is safer and more stable to tow a large trailer with a properly sized weight distribution hitch than without.

Bottom line; my interpretation is the 6.2" Audi made ball mount, provides the full 770 lb. tongue limit when installed on the 2017 Q7.

I estimate my trailer tongue weight fully loaded is about 400 lb., so I think I'll be okay without my weight distribution hitch.

I looked up your Kodiak, and it lists 5,325 lb. shipping weight and 1,275 cargo capacity, so your max. gross trailer weight should be 6,600 lb. The tongue weight for a properly loaded travel trailer is normally 10-12% of total weight (less than this is unstable and can sway). So your max. tongue weight should be between 660 and 800 lb. You are pretty much at the maximum for the Q7 so it is good that you are asking these questions.

Please let us know how your trailer tows with the Q7. I am concerned this is a lot of trailer for the vehicle.

It sure would be nice if an Audi engineer would jump into this forum and clear up the confusion on the Audi specified towing limits.

 

Glad I came across this info, as I've been considering a new Q7 Premium Plus to replace my soon to be bought back Touareg TDI. I have a 23' travel trailer -- about 4500 lbs, 5500 lbs. gross weight. Without a weight distributing hitch, can a Premium Plus Q7 pull this thing? Will I need a Prestige with air suspension? Appreciate any input on that.

As an aside, I've been using the Touareg with a WD hitch to pull my trailer with no issues. After reading this forum, I checked my manual regarding the WD hitch and was surprised to find that it states that the Touareg was not designed for WD hitches. No mention of ripping off the hitch, but.... Don't think I'll be pulling the trailer again with the TDI.

Finally, I have been using a Tekonsha Progidy RF brake controller with the Touareg. Works fine, but one needs a tester to make the vehicle (VW, Audi, Mercedes, others?) see the trailer. I bought this one:
Here's the drill to pair the RF controller:

1. Plug the test unit into the back of the brake controller.
2. Plug the controller into the back of the vehicle.
3. Plug the remote into the cigarette lighter.
4. Start the engine.
5. Turn the power **** to minimum – display flashing 0.0.
6. Depress and hold the manual override and boost buttons – display starts at P.5 and ends at P.A.
7. Press and hold the brake pedal – display flashing 0.0.
8. Set the power **** to greater than minimum – display flashes n.c.
9. Remove test unit and plug trailer into the controller -- display flashes c.

One needs to follow the steps faithfully, but once paired, it stays paired.

 

Hey Snowbird/Ed,

Thanks so much for enlightening me - I just went outside to check my Q7 and found the exact info you described/pictured on the hitch.

It looks like I now have the choice of sticking with the shorter OEM tow ball mount and assuming it will be beefy enough to support the tongue weight OR going with a standard ball mount that meets the spec for weight, but has the potential to risk tow stability.

On the trailer pushing the limits - I agree, but I have given a lot of thought to it and found some things which provide enough offset to keep me within the specified limits.

First thing being that I have the adaptive chassis/air suspension - a lot of reading online says that this makes an enormous amount of difference. Note: I found positive reports of folks towing close to 7000lbs on the Porsche Cayenne, which has the same chassis and air suspension.

Tow limits are generally conservative because the determined safe limit they print on things are a significant distance away from actual tested failure points. This isn't a suggestion that you should mess around with exceeding specified limits, just that people may be arbitrary about adding their own buffers on top of the ones the engineers already did, which may (arguably?) be unnecessary.

Dry hitch weight spec is 586lbs of 5325lbs dry trailer weight, which is 11%. If we assume roughly similar ratio of tow weight to tongue weight upon loading (which granted, may not be true), 11% of the 6600lbs GVWR lands you at 726lbs of tongue weight, which gives enough room for me to be comfortable with below the 770lbs. The catch here is that if I am off by just 1% for the ratio when loaded, we've exceeded max tongue weight - 12% of 6600 lbs is 792lbs

The saving grace though, is that I don't actually plan to tow the trailer any real distance at its loaded capacity. The cargo capacity is around 1200lbs, but I can't imagine us having much more than half of that while on the move at a maximum. We'll always empty our tanks before going anywhere. This puts us back at around 720lbs with a 12% (of 6000lbs) tongue weight. I'll just have to make sure I manage balancing cargo and pay attention to the tongue weight.

Finally, the Audi manual actually suggests driving with as much weight on the tongue so as to be as close to/just under the limit as possible, as it increases tow stability. So it doesn't seem like they see pushing close to the max tongue weight as something to avoid, rather, they are encouraging it. This adds to my thought about engineers adding safety buffers to these limits...I can't see a world where the manual would suggest getting as close to the tongue weight as possible if that was dangerous.

We'll be going to pick up the new trailer at the end of April, so now is just the prep work, but I'll be sure to let you all know how things go as we push the Q7 closer to it's towing limits

 

Hey NMBill,

I am not experienced enough to say definitively if you should not tow with the Premium Plus at that weight / length, however, if you do some reading online about the Air Suspension in the Q7 and Porsche Cayenne, you'll find a LOT of reports saying that it makes a lot of difference.

 

Hi MaximusCub - I agree with your thinking on your trailer loading, and also agree having the air suspension is a great idea for towing a heavier trailer with the Q7.

I have about 20,000 miles experience towing various camper trailers with other SUV's as well as a Ford F150 truck rated at 11,000 lb towing capacity. Some of my trailer/vehicle combinations were near the towing limit of the tow vehicle. At the limit, I found engines struggle with even minor grades on the interstates, and any significant wind will push you around making it difficult to stay in your lane. People don't realize how big the aerodynamic drag due to the large frontal area of a camper trailer is at highway speeds, and combined with even just a 2% grade can make it really hard on the engine. Towing at the limit was nerve wracking and I found myself mentally exhausted after a full day of towing long distance.

However, I am optimistic the Audi engine is more up to the challenge, but you should keep an eye on your engine oil temperature. And the air suspension should really help to keep the vehicle stable with the heavy tongue load.

At your tongue load, another reason to stick with the short Audi made ball mount is because it will help minimize how much the front axle is lightened. One problem with towing heavy trailers is not just the rear squat, but the fact that the load is actually removed from the front axle, which can make the steering feel like it is floating and not really solidly connected to the pavement. On the Audi, the lever arm distance from the rear axle to the ball mount is very short, so the front axle should have minimal load loss. Combined with the air suspension to keep it level, and this will really help you at the limit. The air suspension won't affect the front/rear load split, but it will keep you level.

 

I have the 2017 Prestige with air suspension and am slowly configuring it to tow. I observe that the hitch receiver is lower than the steel suspension described by Snowbird22 (he said "about 16"). I checked the height of the receiver and it is centered at ~14" in Dynamic, ~15" in Comfort. I plan to order the Audi 6.2" ball mount and hope that trailers I have been looking at will match one of my available heights.

Meanwhile, I see this REALLY cheap ball mount that is 6.5": Reversible Ball Mount - 6.5in Length, 3.25in Drop, 2in Rise

(and yes, I'm a total newbie having never towed, so I'm working slowly through this Audi morass)

Other observations about the A/S:
- I can select "trailer mode" in either Dynamic or Comfort (height 2 or height 3--height 1 is the lower rear position for loading)
- Once in "trailer mode", I can still adjust upwards from Dynamic to Comfort, but I cannot adjust downwards. I can go from Comfort to Dynamic, but it remains in height 3. I guess this is a machine safety feature?

Questions:
- Does anyone know for certain what the "towing controller" does? I've seen allusions that plugging a trailer into the hitch cause it to tell the car how to manage the shift points and perhaps the A/S
- Does anyone know what the A/S "trailer mode" does? How does it differ from behavior caused by plugging a trailer into the hitch?

 

Hey tomp22,

That ball mount is a little longer than the Audi part, and is rated for 600lbs tongue weight and 6000 lbs trailer weight. I'm not very experienced, but I would _guess_ you'd probably be just fine with that if you're under 4000lbs, since the extra length is really about control of what you're towing. Aerodynamics of the trailer come into play too.