Audi TT Mk2 (8J) - Tow Bar Installation and Connector Wiring for a Thule Bike Carrier

   #1  

SwissJetPilot

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Evidently the Audi TT Mk2 was never rated by Audi for towing. However a company called GDW Towbars (https://www.gdwtowbars.com/) has manufactured a tow bar specific for the Mk2. According to the GDM documentation, this tow bar has been certified for use on both the Mk2 (8J) Coupe and Roadster in accordance with Kraftfahrt-Bundesamt and TUV Certification. There is also an American company called Curt Manufacturing that makes a 1.25" receiver that can also be used for a bike carrier for both the Mk1 and Mk2 (https://www.curtmfg.com/part/11765).

While American DMV seems to be a bit less strict when it comes to these types of devices, I decided to also contact the National Trailer and Towing Association Ltd (UK) and their take is that the GDW tow bar is not approved (in the UK) for towing since Audi never rated the TT for towing. However they didn't see any problems with using for it to support a bike carrier. I'm going to assume this would also be true for the Curt Manufacturing version too.

My question is whether or not the Audi TT Mk2 will accept retrofitting and coding of a VAG Tow Module P/N: 1K0907383F. which is common across multiple VAG vehicles. According to Uwe Ross, once the module is installed, it has to be recognized and installed using VCDS. However will this still work if the vehicle was never intended for a tow module, as would be the case for a TT?

If the Tow Module can't be retrofitted, does anyone know if it's possible to wire a 7-pin connector for a Thule bike carrier (European version) by tapping directly off the tail lights given the issues of PWM (Pulse Width Modulation).

Cheers! - Swiss

https://forums.ross-tech.com/index.php?threads/15471/

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Scroll down the list until you see 69-Trailer.
Check the box next it.
[Save Coding]

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   #2  

Uwe

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I'm confused. If you're only using it for a bike carrier, why would you need anything beyond mechanically installing the receiver? Does your bike carrier have its own lights?

But in any case, the second-gen TT is basically an Mk.5 / 8P A3 from an electronics standpoint. I don't see any reason why an appropriate trailer control module couldn't be made to work.

-Uwe-

PS: Since you're contemplating a trailer hitch retrofit, I'm moving this to Retrofits.
 
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SwissJetPilot

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"Does your bike carrier have its own lights?"

Yes. Here in Europe (and the UK), bike carriers have to have lights and second license plate since the bikes block the view of the ones on the vehicle. Same with cargo carriers as shown below. Since they are connected into the tow bar receiver, they use the 7-pin connector.

Okay, thanks Uwe. :) I'll take a look at a Mk.5 / A3 wiring diagram and see if I can figure out how to wire up a tow module.

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DV52

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@SwissJetPilot: With absolutely no offense intended - I'm with @Uwe; installing a hex69 module for no other reason than to operate the lights on a bike-rack seems somewhat of an overkill, if not needed!

Before you spend the money and the time to install the module - why not try hooking-up the bike lights directly using a temporary arrangement?

It's not clear from your pictures- but I assume that the bike-rack lights are LED. If the additional electrical load on the existing lights don't trigger a CAN error- you might be lucky enough not to need the module at all - maybe?

Anyhow, worth a try - I think

Don
 
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Uwe

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I'm with @Uwe; installing a hex69 module for no other reason than to operate the lights on a bike-rack seems somewhat of an overkill, if not needed!
That's not exactly what I said. I'd simply never seen or heard of a bike rack or cargo carrier with its own lights on it before.

If wiring them directly doesn't work, I might consider making a little slave circuit where the only additional load on the existing lighting circuit is the gate of a MOSFET, which would be quite negligible.

-Uwe-
 
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DV52

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That's not exactly what I said. I'd simply never seen or heard of a bike rack or cargo carrier with its own lights on it before.
Yes - on re-reading your reply, I understand the difference now. Apology

If wiring them directly doesn't work, I might consider making a little slave circuit where the only additional load on the existing lighting circuit is the gate of a MOSFET, which would be quite negligible.
haha-- Now there's a true engineer's solution!! :thumbs:

Are MOSFET switches really needed here - maybe just as easy to use bog-ordinary micro relays (they are mercifully slower in a PWM environment)?

But I agree, your suggestion is probably better suited to this problem than the alternative of installing a fully fledged hex69 module.

Don
 
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SwissJetPilot

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I stumbled upon this module from Urbeni (Kit 7C #40947). The basic UEK-7C module only requires splicing directly into the tail lights and the module takes care of the CANBUS issues.
(http://www.urbeni.com/universal_electric_kit_module.aspx)

I also found CANBUS tow module kits from Eric Jaeger (DE) and ECS Electronics (NL), but they require additional jumpers into the fuse box and quite a bit of re-pinning into existing connectors. For just hooking up the lights for a bike carrier, the Urbeni UEK-7C may be the easiest solution.

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chillout1983

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hi I have actually just installed a towbar on my passat for the same reason to carry 2 e bikes as they are too heavy for my roof racks I used the VW electrics (westfalia) the wiring is straight forward and weirdly everything worked before being coded apart from the parking sensor mute and the display of a trailer on the navigation screen once coded these functions work
 
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SwissJetPilot

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@ chillout1983 - Is your Passat rated for towing? I suspect that it's already pre-wired to take the VAG tow module. Did you do this yourself or have it done...any wiring instructions you can share?
 
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chillout1983

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Hi I ran the harness all the way from the the Boot/trunk its grounded in the rear quarter panel, 3 constant positive feeds and 1 switched at the fusebox in the dash the can bus pins are removed from the BCM inserted in to the harness then the harness can bus pins re inserted to the BCM (splitter) another cable is removed from the bcm and connected to the harness and the harness connected to the BCM I believe this is a back up for the brakes if the Bus fails.

Link below you can select your car/similar for wiring kit instructions they have an international site

 
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There is an aftermarket module that links into the lights at the rear and a 12V supply: model: TEB7AS

I have one in my Touran which works fine, and even takes into account that the Touran uses the same 21W bulb for Brake and tails = the module switches on the trailer brake lights when the tails switch to brake brightness. I use it with incandescent and LED systems. I powered it from the supply to the 12V DC outlet in the boot.

It does tick with the indicators, and has a secondary beeper with indicators, when the trailer in plugged in.

They're about 20 or 30 UK Pounds?
 
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