skideeppow

yes, i know another thread on this. After reading all this info (and there was a ton of great stuff) i also purchased a cheesy Curt hitch. The people at Drawtite were super helpful and after a lot of reasearch i pruchased these two accessories 56146 which is the wiring harness and the 55151 which is a eletric cord that goes from the harness to the front battery. They told me that this is so the eletric pulls the power directly from the battery and not the eletrical.
This will prevent the trailer from shorting the eletric sysyem.
Does this sound right? If so, does anyone have some detailed insturctions on how to connect? The only thing i found was instal for the audi 13 pin harness.
thanks

Todd Beaulieu

I'm just as confused as you are. In fact, I came here to post yet another question asking this very thing.

I've read so many posts my eyes are swimming. Yet I still don't know what the bottom line is. At first I was horrified to read that I needed a $150 harness. I'm now to the point where I'd GLADLY pay that if I could just find one!

If I understood exactly what's needed electrically by the car, I'd like to think I could wire it up myself.

I even sent Audi an email expressing my discontent with them leaving us high and dry like this.

I just searched drawtite's site and found neither of those part numbers. Not a surprise in this top secret project.

We should work through this issue together and post the BOTTOM LINE so others will know what to do!

JustMtnB44

First off, what model year cars do you guys have? If they are 2002 or newer, they should already have the Euro 13 pin trailer plug wired in. Look under the middle of the rear bumper, it will be stashed up there. If you don't have the euro plug pre-wired, then I recommend you do it while it's cheap; on sale here at ECS Tuning.

If you do have the euro plug, then you can either buy or make an adapter to get a standard flat 4 pin US plug. Here is one you can buy from Eurohitches but it is currently backordered, I don't know when it will be available.

It is fairly straightforward to make an adapter. All you need is this Euro plug and this converter plug. Just match the leads on the converter to the Euro plug in the diagram below. The park/tail/marker lead goes to either pin 5 or 7, or they can probably be connected together but I'm not sure if that will cause issues. I'm ordering the parts today so I can build this and make sure it works. This post is basically a compilation of info I have found while searching here and on quattroworld.

Pete@ECSTuning

Wow! fantastic info!

Todd Beaulieu

DISCLAIMER: By no means do I know what I'm talking about, but this is what I've come up with so far.

I did some more research. While it's starting to sink in a little more, there's still one major question on my mind. More on that in a moment.

I agree with your assessment on the 13-pin connector (ISO 11446), which will allow us to plug into the factory socket under the bumper (which I do have), as opposed to tapping into wires, which I feel is a hideous solution.

I would change your proposed module, however, for a powered module. Such a unit would allow us to use the constant 12v feed from the 13-pin socket, so the trailer lights aren't drawing power from the existing light circuits. Additionally, I'd use a module that accepts left and right turns, stop and running lights as separate inputs. The part 56146 mentioned in the original post is actually a Curt product, which is what you'd need. Since we have constant 12v at the 13-pin, we would NOT need that additional kit mentioned.

According to Audi a company called Hopkins made the OEM converter for Audi (mfg part # 110 203 00, Audi part # ZAW 808 003). I called them. They have no idea what I'm talking about.

Back to the "big question".

When the OEM module is plugged into the car (and trailer?), the ECU knows it's towing and makes a number of adjustments, such as braking, shifting, suspension, backup sensors and trailer light monitoring.

I'm fairly certain that if I were to obtain that 13-pin connector and solder in a purchased module (like this curt unit), I'd be in business. What I'm not so sure about is whether the car will see things in the same manner as it would with the OEM part. I don't know if the original module "talked" to the car somehow to let it know, or whether the car simply sees a draw on one of the lines and assumes it's towing. I don't see any pins on the diagram that look like they could be used for communication so I'm guessing (and hoping) for the latter scenario.

If shipping time/cost is an issue getting that connector, maybe we could go in on an order for a few units. It seems like the logical starting point to me.

Todd Beaulieu

I forgot to mention. Count Eurohitches out. He is a terrible vendor. I left one voice message and two emails over the course of a week ... two weeks ago. No response.

JustMtnB44

I thought about it some more and I agree with you. The other part was from a post on QW. In fact this Converter module would be perfect as it already comes with a 4 pin connector on it. So in this case the the wiring would be:

Conveter box -> Car 13 pin plug
Batttery -> Pin 9
Right Turn -> Pin 4
Stop -> Pin 6
Left Turn -> Pin 1
Tail -> Pin 5 or 7 or maybe both
Ground -> Pin 3

Is that what you were thinking? I don't see why that won't work, so I'll probably get that module instead of the other one.

Where did you find that? Apparently the only thing that gets disabled is the backup sensors. There are no changes to tranny or suspension. See this thread on QW for more info on that.

Apparently just plugging anything into the euro plug makes it work properly. If you want I will order 10 Euro connectors from that UK site. That amount gives the best balance of shipping costs. If we bought them individually, it would cost $24 each shipped. If I buy 10 and them ship them out to people in the US it would cost $20 each, so we would all save a few bucks. In fact, consider it done I will do it right now.

JustMtnB44

Ok so after looking into this a little bit more, here is where I am at.

It appears as though the factory wiring harness already isolates the trailer lights from the car lights. Therefore, the powered converter unit should not be required. I am going to try this converter unit. It is cheap, provides the functionality required and is built into a 4 pin flat plug so it will be less parts and easier to handle. Also, this solution will end up looking just like the OEM adapter.

Hopefully I will have all the parts so I can test this next week. I have ordered 10 of the Euro plugs, so if anyone needs one of those or wants me to make them a complete adapter plug just PM me.

- Justin

Todd Beaulieu

The built in adapter isolates the circuits? That's amazing.

Audi called me today and left a message, telling me they are investigating my complaint that they left us high and dry with no support for towing.

At the absolute very minimum they should produce documentation thoroughly describing the wiring that's in the car, as well as what's required to hook into it. They should also document exactly what the car does (if anything) when it senses something's being towed.

skideeppow

wow left this post for a day and look what i come back to find. I know nothing but will take one of those euro eletrical power thingy's you are going to order from europe. I am having my hitch put on Monday so i might just wait on the eletric.
thanks