DIY: B6 A4/S4 - Trailer hitch installation

**dubbinchris** · 02-18-2013 10:08 PM

Originally Posted by A4avanttt

What kind of combo is this ball and hitch? Also when the ball is removed is the hitch hidden? That is a sweet setup.

It's a Westfalia hitch. Yes when removed its completely hidden. I ordered it from PF Jones but its not the link listed above. That one is only detachable by unbolting the ball. I got item #305-206. It was 155 British pounds to buy and 105 British pounds to ship. Just look up the current rate conversion and call them. They will take your CC# over the phone. They were very pleasant to deal with and it arrived in less than a week. I had to do some alight modification to the alum bumper under the cover since the US bumper and Euro are slightly different. The bumper cover went back on with no problem. Also a word to note. There is only one ball size in Europe...50 mm. It's a slight but smaller than a standard US 2" but the difference isn't enough to cause any problems. You can see in the photo further up the 3700 lbs of boat and trailer I hauled with it. The US hitch from CURT only has a tow capacity of 2000 lbs whereas the Westfalia is about 4400 lbs. I was also 100% against drilling into the spare tire well so the Curt was out in my book. No drilling required on the Euro but more disassembly.

**KiddEng** · 06-27-2013 07:45 AM

to the OP; do you have the pictures hosted up somewhere? Looking to do this install to tow my bike around for track days.

**a4audi4fun** · 06-27-2013 12:40 PM

Originally Posted by KiddEng

to the OP; do you have the pictures hosted up somewhere? Looking to do this install to tow my bike around for track days.

https://www.curtmfg.com/masterlibrar...111640_INS.PDF

Installation manual is here - the B6 model requires holes to be drilled in the spare tire well. On my B7 2008 Avant no drilling is needed; the hitch attaches directly to the rear exhaust bracket mounting point and the rear towing point. No drilling was needed for my installation.

**KiddEng** · 06-27-2013 01:06 PM

Originally Posted by a4audi4fun

https://www.curtmfg.com/masterlibrar...111640_INS.PDF

Installation manual is here - the B6 model requires holes to be drilled in the spare tire well. On my B7 2008 Avant no dirrling is needed; the hitch attaches directly to the rear exhaust bracket mounting point and the rear towing point. No drilling was needed for my installation.

Awesome thanks... yeah originally i looked up the Curt and was shown the 111640, ordered off amazon prime. then after more digging and reading in the avant forum, saw that the 07-08 models from Curt work straight bolt on! (111803) and promptly cancelled the original order for this one.

Do you have any pics of how low this is going to hang?

**a4audi4fun** · 06-28-2013 07:45 AM

Originally Posted by KiddEng

Do you have any pics of how low this is going to hang?

Pics from my gallery here on Audizine...

http://www.audizine.com/gallery/show...bumper&cat=500

http://www.audizine.com/gallery/show...r-012a&cat=500

**KiddEng** · 06-30-2013 08:45 AM

awesome thanks man! that looks pretty good and not too low!

well I looked at the wiring harness i got that was recommended by etrailers website and curt...the 56201, and it doesn't have the brake wire option (doh!). Ordered the 56200 that does and will have to wire at a later time. Hitch is going in today though. Did you go with this harness 56201 or a different one? I'm hoping its not that big of a deal as i need this wired for next track day..

**lookaught** · 06-30-2013 09:26 AM

Originally Posted by KiddEng

to the OP; do you have the pictures hosted up somewhere? Looking to do this install to tow my bike around for track days.

Somewhere yes, but it will take some time to find them. They were hosted on a domain that I no longer use, but I think I have them on an old computer. They are not applicable to a B7 install because you have a bolt on hitch.

Installing the hitch isn't that hard, it just takes a little time. With a B7 I imagine it'll be super easy. The wiring is also pretty easy if you know what wires to tap, read post 14 and post 23, which includes the different wires you need to tap for a B7 (post 14). Honestly the most annoying part is getting the trim off, and taking time to tuck the wires neatly so they don't show. I thought I posted which modulite I used but I guess it was a picture and not written. It was this one I think:

http://www.etrailer.com/Wiring/Tow-Ready/119190KIT.html

Its really simple. You need to find a wire to:
Power
ground
left turn signal
right turn signal
brakes
running lights

Wire the power to the cigarette outlet or to the battery. Then tap all of the other lines, described in the posts.

What kind of bike do you have?

**a4audi4fun** · 06-30-2013 09:30 AM

I'll leave it to lookaught to answer the questions on the harness. I don't tow - only use mine for my bike rack so no need for extra lights.

**KiddEng** · 06-30-2013 12:07 PM

Originally Posted by lookaught

Somewhere yes, but it will take some time to find them. They were hosted on a domain that I no longer use, but I think I have them on an old computer. They are not applicable to a B7 install because you have a bolt on hitch.

Installing the hitch isn't that hard, it just takes a little time. With a B7 I imagine it'll be super easy. The wiring is also pretty easy if you know what wires to tap, read post 14 and post 23, which includes the different wires you need to tap for a B7 (post 14). Honestly the most annoying part is getting the trim off, and taking time to tuck the wires neatly so they don't show. I thought I posted which modulite I used but I guess it was a picture and not written. It was this one I think:

http://www.etrailer.com/Wiring/Tow-Ready/119190KIT.html

Its really simple. You need to find a wire to:
Power
ground
left turn signal
right turn signal
brakes
running lights

Wire the power to the cigarette outlet or to the battery. Then tap all of the other lines, described in the posts.

What kind of bike do you have?

Thanks no need for pics anymore lol, i originally was wanting to look at pics b/c the Curt hitch i ordered was the drill required kind; I was able to cancel that one and ordered the "bolt-in" hitch for the later B7 models. Actually just finished installing that 10 mins ago, piece of cake!

I found another thread that indicates which wires to tap in the rear, now i'm just waiting for that harness to come in.

Thanks to you and a4audi4fun, for the help!

I have a 05 cbr600rr, going to the track for the first time next weekend and using the avant as the hauler.

**foley803** · 06-30-2013 12:13 PM

So you're saying that there is a bolt on alternative for the B6? (Using the B7 hitch)

**KiddEng** · 06-30-2013 12:58 PM

Originally Posted by foley803

So you're saying that there is a bolt on alternative for the B6? (Using the B7 hitch)

not sure how the B6 bolt pattern is for the exhaust hanger, but model #111803 from Curt; listed for the 07/08 B7 bolted it on my 06 in 20 mins.

http://www.catalograck.com/ImgVD/CUR/CM_111803_INS.pdf

install instructions; if you take a peek under your B6 for similar pattern it may fit?

I originally was interested in this thread b/c the drill in Curt hitch was recommended for my car as well.

**profase** · 10-15-2013 12:23 PM

Thanks for this! Installed the hitch on my 2007 A4 sedan and it pulled a trailer of canoes (~600lbs) with no issue whatsoever.

A note on the left tail light wire connector: it follows the mirror image of the right tail light connector (reference post #14 for the right tail light connector). By mirror image, I mean imagine the right connector was flipped over to the left side.

Cheers,
John

**nickbischoff** · 05-20-2014 01:29 PM

Pictures are broken, was wondering if you could re-upload them? Thanks

**T0M3K** · 05-21-2014 09:11 AM

I have the same hitch installed and it is a bit weak, I managed to bend it with 2 bikes on bike rack, I will have somebody reinforce it

**a4audi4fun** · 05-22-2014 06:50 AM

Originally Posted by T0M3K

I have the same hitch installed and it is a bit weak, I managed to bend it with 2 bikes on bike rack, I will have somebody reinforce it

How did you manage to that? Got any pics? These are Class 1 hitches so tongue weight is rated 200 lbs but should handle a little more. For the B7, it also attaches to the rear towing hook so there is a reasonable amount of additional support against flexing - look for the silver coloured portion in my pics in post #85.

**T0M3K** · 05-22-2014 07:54 AM

Originally Posted by a4audi4fun

How did you manage to that? Got any pics? These are Class 1 hitches so tongue weight is rated 200 lbs but should handle a little more. For the B7, it also attaches to the rear towing hook so there is a reasonable amount of additional support against flexing - look for the silver coloured portion in my pics in post #85.

https://drive.google.com/file/d/0B-E...it?usp=sharing

The towing hook on right side helped keep it in place, but the other side had no support and in rotated down. Bike rack weighted a little over 100lb, but since I drove through NYC, all those potholes must created insane stress on it. Also, I didn't put a a safety strap (the one that attaches to rack and trunk to limit sway. So all combined efforts yield above damage

**lookaught** · 05-22-2014 11:25 AM

Wow, did it tear or stretch the metal tire well that it was bolted to? Or were bolts loose?

I've put a ton of stress on my hitch and have had zero problems in five years. Maybe your bike setup just created to much torque

sent from my banana phone.

**lookaught** · 05-22-2014 11:27 AM

Originally Posted by nickbischoff

Pictures are broken, was wondering if you could re-upload them? Thanks

They were hosted on my brothers server that isn't active anymore. I'll ask if he still has copies. He said a while Back that he does but getting him to find them is harder than turning my car into a spaceship

sent from my banana phone.

**T0M3K** · 05-22-2014 11:39 AM

Originally Posted by lookaught

Wow, did it tear or stretch the metal tire well that it was bolted to? Or were bolts loose?

I've put a ton of stress on my hitch and have had zero problems in five years. Maybe your bike setup just created to much torque

sent from my banana phone.

I think that's what happened. I will have a guy weld additional support. I plan to tow ATVs in the future

**T0M3K** · 06-26-2014 05:49 PM

Before:
https://drive.google.com/file/d/0B-E...it?usp=sharing

After:
https://drive.google.com/file/d/0B-E...it?usp=sharing
https://drive.google.com/file/d/0B-E...it?usp=sharing

We straighten it and added cross member to reinforce it. Channel got small screws to help prevent rocking of attachment

**SJorge3442** · 07-31-2014 10:56 AM

lets bring this back up. Is there a better option for this nowadays? I just got a jet ski and I wanna pull it without having to borrow my dads wrangler or f150.

**choppper** · 08-19-2014 06:50 AM

I just installed the Curt hitch (Part# 111643) and the Hopkins Wiring kit (Part# 46365) for trailer lights on my 2003 B6 A4 sedan.

Since I have a sedan I used this guide though: http://www.audiworld.com/tech/elec184.shtml.
Everything works great so far! I bought a rack carrier for the hitch as well as a 2-bike carrier that work great. Last night I picked up my 14' boat to really test the car. I have a automatic tranny in my 1.8T with a K04 (not chipped unfortunately so I have over boost conditions always). It pulled really nice, I started out in manual mode but eventually switch to normal drive mode because I hate how its not always a smooth shift in manual mode. No issues at the landing or anything! I must say the boat is quite light though, it has a 25 horse engine and the tongue weight it maybe 60-80lbs?

**SJorge3442** · 08-19-2014 07:06 AM

is the hitch hidden when not in use? I dont want to be driving aroudn with a receiver stick out of the back all the time. my jet ski tongue must be like 60lbs, plus a 400LB hull/motor. Cant wait to get a hitch so I can stop using my dads F150 to pull it around.

**choppper** · 08-19-2014 07:16 AM

It is not completely hidden like the more expensive European version, but it's not to bad.

It's nice to haul something around, yes I know its not cosmetically pleasing to everyone out there but hey when you have to pay the mortgage and other bills its not so easy to just buy and insure a second tow vehicle!

**SJorge3442** · 08-19-2014 07:55 AM

Originally Posted by choppper

It is not completely hidden like the more expensive European version, but it's not to bad.

It's nice to haul something around, yes I know its not cosmetically pleasing to everyone out there but hey when you have to pay the mortgage and other bills its not so easy to just buy and insure a second tow vehicle!

thats not terrible. Looks like you are running the same tires as me too. Alitmax Hp's?

**choppper** · 08-19-2014 08:54 AM

No It doesn't look bad or stand out awkwardly in my opinion. Yes I am, got a killer deal on them from tirerack.com 4 tires shipped for $400 and a $50 visa rebate card.

**T0M3K** · 08-19-2014 09:32 AM

I tow ATV with it now:
https://drive.google.com/file/d/0B-E...it?usp=sharing

**choppper** · 08-19-2014 09:41 AM

Sweet T0M3K, these things can defiantly tow! Manual or auto tranny?

**SJorge3442** · 08-19-2014 09:45 AM

Originally Posted by choppper

No It doesn't look bad or stand out awkwardly in my opinion. Yes I am, got a killer deal on them from tirerack.com 4 tires shipped for $400 and a $50 visa rebate card.

yeah I got them from tirerack too. I wish I would have gotten wider than 235 had I known they would be as skinny as they are. my Eagle GT's in 235 were much wider. Oh well. The deal was too good to say no too. They perform pretty well in wet weather too.

The hitch will be coming to me during the winter. That is, unless I upgrade to a B7 avant.....

**choppper** · 08-19-2014 09:56 AM

Originally Posted by SJorge3442

yeah I got them from tirerack too. I wish I would have gotten wider than 235 had I known they would be as skinny as they are. my Eagle GT's in 235 were much wider. Oh well. The deal was too good to say no too. They perform pretty well in wet weather too.

The hitch will be coming to me during the winter. That is, unless I upgrade to a B7 avant.....

I can't complain about the width I don't feel they are to skinny but I came from the cheapest tires before these, never again will I buy the worst tires lol, they were so loud! Cool to hear they are good in wet weather, winters the real test here in MN! But I only have gotten stuck once because I stopped somewhere with to much snow and my bottom was hung up lol.

Why wait until winter if you want to haul the jet ski you need to do it now!
I would love to upgrade but I think I will keep this car till the end and upgrade when I can to a B8, I think they look better personally, but hey thats my opinion! Until then I will drive my B6

**arneefreeman** · 09-16-2014 04:38 AM

Hello.
Does anyone know if there is an hole for wiring on the B6 A4 avant body or must I make one by myself? I fitted OE towbar (AL-KO), but I cannot find any hole where to put wiring loom in :( and that would be a shame to make a hole and after then realise that there is one somewhere around :)

p.s. Any wiring diagrams are welcomed because I dont have them :)

**diagnosticator** · 12-12-2014 02:04 AM

Originally Posted by dubbinchris

That is the OEM style trailer hitch.

**pimpbot** · 02-24-2016 11:21 AM

I just did my wiring on my 2007 Avant. Easy, once you figure it out, but a PITA to take everything apart to get back to the wiring.

I bought a Bentley Manual when I first got the car a bit over a year ago. Is it me, or are the wiring diagrams now like impossible to find in this book? It used to be pretty easy to follow.

I just took tips from this page about wiring it up... use the third brake light for brake, use the license plate light for taillights.

I have one issue, tho. I got a cheap-ish trailer wiring harness. On the plus side, it has zero (or so close I can't read it with my Fluke clamp meter) parasitic current drop when not in use. On the downside, it isn't solid state. It has relays, and I can hear them clicking when in use. When using my turn signal, I can actually hear the relays buzzing.I assume Audi is using some sort of duty cycle PWM kinda voltage to the bulbs... being they are single filament bulbs, and used for taillights AND brake lights. I assume this PWM signal is what is freaking the relays out causing them to chatter when I put my turn signal on. It makes me want to put in a defeat switch so it's turned off completely when I don't need it. I should probably just find a fully solid state transistor switched one. Well, at least I seem to be getting clean-ish output to the trailer harness. I haven't hooked up my trailer yet.

I think I also read somewhere that the sedan doesn't do this. The sedan has separate bulbs or at least separate filaments in the bulbs for the different functions. Is that true?

**aviator79** · 03-29-2016 10:25 AM

Just picked up the curt 11164 from autoanything for $118.99 shipped for 2006 Audi A4 sedan. OP says comes with ball mount. Does it or do I need to get a 1-1/4" ball mount?

**lookaught** · 03-30-2016 08:47 AM

I bought a truck a while back so I don't tow anymore with the Audi but still use the hitch for my bike rack.

**incubusfc** · 09-19-2016 06:30 PM

So I bought a hitch kit off of ebay and it says it's for b6 a4. It's a curt, also came with wiring shit.

The wiring shit is kit 59201. It only has 4 wires going to the module thingy. I'm guessing this isn't correct as each function is a separate bulb? So I need to get one that has wires for brake, r turn, l turn, power and ground? Or can I still use this one that only has power ground L and R?

**road_tripper** · 09-19-2016 06:54 PM

you need a 5-wire to 4-wire converter.

brake, left, right, tail/running lights, ground -> tail/running lights, brake/left, brake/right, ground

**pimpbot** · 09-19-2016 08:44 PM

Originally Posted by lookaught

I bought a truck a while back so I don't tow anymore with the Audi but still use the hitch for my bike rack.

Sweet Tallboy! I love that bike.

**pimpbot** · 09-19-2016 08:48 PM

Originally Posted by incubusfc

So I bought a hitch kit off of ebay and it says it's for b6 a4. It's a curt, also came with wiring shit.

The wiring shit is kit 59201. It only has 4 wires going to the module thingy. I'm guessing this isn't correct as each function is a separate bulb? So I need to get one that has wires for brake, r turn, l turn, power and ground? Or can I still use this one that only has power ground L and R?

I'm not sure about the B6, but my B7 Avant uses different voltages on single filament bulbs for brake/turn/tailight. As in, it pushes like 9 or 10 volts to the bulb for taillight, and bumps the voltage up to 13v for brake lights. Makes it not usable for LED brake and taillights.

I had to get creative about this. I used the high third brake light for the brake, one of the rear markers that is not lit brighter with the brakes as the taillight, and I think I used the side markers for turn signals. I managed to get all of this in the rear taillight wiring of the car. It was a PITA, but it works.

Yeah, I mostly use my hitch for bike rack. I have a small utility trailer for moving appliances, garden/construction equipment (I moved a soil compactor once) and furniture that maybe sees pavement about once a year. I guess it was cheaper than renting a pickup.

**diagnosticator** · 09-23-2016 11:11 PM

Originally Posted by lookaught

Got any info on this OEM setup? I read it is not available in the USA, I certainly couldn't find it. The Curt hitch is a far cry from a perfect solution, but for a little over $200 it's effective and a lot cheaper than a new tow car!

Necro post I know.

Here is the info for the OEM trailer hitch from Partslink24.com.