Trailer brake controller and wiring?

I'm considering adding brakes to my 3000 pound GVW trailer and have found a compatible electric brake setup. Now I need to upgrade from the usual 4 wire lighting to a 7 wire setup and add a brake controller. Sounds like the brakes require 20 to 30 amps, which I suspect means wiring directly to the battery? I've a choice of two Golf TDIs- a 2003 and a 2015. Any suggestions?

If you already have the typical 4-wire on both, then upgrading the additional wires to get to 7-wire is really only adding: Aux charging, Backup Lights, and Trailer Braking. The only one that might be challenging of those on the 2015 is Backup lights depending on how CanBus handles it? On my 2006, I added a backup light wire to a typical 4-wire setup to allow the reverse lock-out solenoid to work on my utility trailer with surge brakes. To get that wire, I simply stole power out of a connector in the trunk. (I'll need to do this to the 2013 one of these days if I can get my wife to leave it home on a Saturday so I can work on it...)

I honestly don't know how much current an electric brake setup needs to function. E-Trailer shows a 40A auto-reset circuit breaker on their wiring diagram. (I run hydraulic surge disc brakes on the utility trailer I drag fully loaded through the mountains to get to Maine.)

Yes, your e-brakes are going to need more current than the lighter socket in the trunk will provide.

A 10-12 gauge run from the battery thru a auto-resetting breaker (not a fuse that won't reset by itself) is the standard way this is done in the trailer-wiring biz.

Brakes this big suggest another point: either of your tow vehicles being rated to tow 3000 lbs is something to confirm as well. Best to know in advance if your insurance company will duck a claim if the recommended GVW towing weight is exceeded.

Vince Waldon said:

Yes, your e-brakes are going to need more current than the lighter socket in the trunk will provide.

A 10-12 gauge run from the battery thru a auto-resetting breaker (not a fuse that won't reset by itself) is the standard way this is done in the trailer-wiring biz.

Brakes this big suggest another point: either of your tow vehicles being rated to tow 3000 lbs is something to confirm as well. Best to know in advance if your insurance company will duck a claim if the recommended GVW towing weight is exceeded.

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That's one of the considerations here, the heaviest load is a 650 kilo or so tractor on a 150 kilo trailer. IIRC the U.S. manual for the 2003 gives a 1000 pound tow rating but the rest of the world got a rating of half the empty weight (about 700 kilos) without brakes and 1500 kilos with brakes. The 2015 has the dual clutch automated manual so it's not rated for towing in the U.S. but rated for half empty weight without brakes or 1500 kilos with brakes most everywhere else. VW could try to deny warranty on the 2015 for towing, but they'd have a weak argument as it's twin the Audi A3 with the same powertrain is rated for towing. From a practical point of view the readily available at reasonable price Curt hitches for both vehicles are rated for 200 pounds tongue load and 2000 pounds total towed weight, and the tractor and trailer with brakes weight about that.

On the MK7 getting the brake signal to your trailer brake controller is kinda tricky. I tapped A57 on the BCM. It goes to the third brake light, which is an LED and isn't generally checked for a bulb out error by the car. I had tapped the signal wire from my pedal on my MK6 and it did some wacky things with the controller that I wanted to avoid. I will get a bulb out error if I pull the brake lever on the controller a few times when no trailer is connected, but it has never been a problem when one is. I used OEM trailer wiring, which provides for backup lights, but if I were adding a brake controller from a 4 wire, I'd probably just skip the backup lights.

Here's my install if it can be any assistance. http://forums.tdiclub.com/showthread.php?t=478382

This can also be used to avoid going trough your firewall or running wires under your car.
http://forums.tdiclub.com/showthread.php?t=485095

I used Tekonsha P3 brake controller on my JSWs but I am using a REDARC EBRH-ACCV2 Tow-Pro Elite Controller at twice the price since it mounts better.
I tapped the (I think ) blue and red brake wire at the brake switch in the JSW.
The brake controller power should come directly off the battery and have a fuse or breaker inline. I used two 30 amp circuit breakers, one for the brake controller and one for the trailer power. I also added a relay that kept the trailer from draining the battery with the engine not running.
The problem for me was not getting a trailer module that could be coded for NAR. I had to add a switch to fake the module I had into trailer mode and use a tail light converter to drive the trailer combined brake and turn lights.
I towed a 16' Scamp trailer with both my 2009 and 2013 TDI JSWs bith with Westfalia OEM style hitches.
I let VW buy those tow back and bought a 2016 Town and Country to tow with and I am now setting up a 2012 Touareg for the task.

When I had the brake signal wire on my MK7 tapped, my Tekonsha P2 would come on even if the ignition on the car were off when I touched the brake pedal and the numbers on the display would run all over the place. After I switched it to just the the third brake light wire, it stopped all the weirdness. I doubt it really hurt anything, but I didn't like it. Having installed the euro wiring harness, I was forced to be pretty familiar with the BCM, so it wasn't any harder more work than figuring out which wire to the brake switch is correct. The wire from the brake switch goes directly to the BCM. On a MK7, you can see all the BCM light pin assignments in your adpmaps.

You need to get a lighter trailer! I have towed a lot with my Golf and have found that the engineers were right with 1000 lbs is the max you should tow. Pulling a heavy trailer just means you are pulling dead weight and not allowing weight for your load. I use a 5 x 8 trailer with a wire mesh floor from Northern Tool- https://www.northerntool.com/shop/tools/product_200671883_200671883
Its light weight plus works well but load it to anywhere close to 1000 lbs and I have found you will be dropping into 3rd gear at 55 mph 3500 rpm going up 6% inclines. I would spend your money on a new lighter weight trailer.

I pulled a 1985 Scamp 16' camper with my 2009 and 2013 TDI JSWs using the OEM Westfalia hitch with tow module and electric brakes (P3).
The JSWs both towed the trailer easily and with the brakes stopped well also.
One issue is the tongue weight limitations and correcting for that weight with air bags.
They would be much better if weight distributing hitches were available.
I just let the transmission take care of itself.
The trailer module recognizes the trailer and adjusts the engine and transmission maps to better handle the trailer loads.
VW even says that the Touareg (rated to tow 7700 lbs is not meant to tow!
The 2.0 TDI JSWs have no problem towing whatever as long as it is properly balanced.
By the way the towing limits on the trailer tires limits the max speed to 65 mph and towing the Scamp (2800 lbs) netted 25 mpg.
All of that being said when we replaced the recalled VWs we bought a 2016 Town and Country and it tows better because it is a larger longer wheelbase car, but the gas motor rated 283 hp really does not pull any stronger than the 2.0 TDI did. Torque does the pulling and the Diesel has the torque.

Hwycruiser said:

You need to get a lighter trailer! I have towed a lot with my Golf and have found that the engineers were right with 1000 lbs is the max you should tow. Pulling a heavy trailer just means you are pulling dead weight and not allowing weight for your load. I use a 5 x 8 trailer with a wire mesh floor from Northern Tool- https://www.northerntool.com/shop/tools/product_200671883_200671883
Its light weight plus works well but load it to anywhere close to 1000 lbs and I have found you will be dropping into 3rd gear at 55 mph 3500 rpm going up 6% inclines. I would spend your money on a new lighter weight trailer.

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You might be a bit short on power...I don't disagree with a lighter trailer being generally better, but a stock ALH should pull 1000 lbs up a 6% grade in 4th at 60 MPH unless it's shaped like a parachute .

The answer is always - more power .

Hwycruiser said:

You need to get a lighter trailer! I have towed a lot with my Golf and have found that the engineers were right with 1000 lbs is the max you should tow. Pulling a heavy trailer just means you are pulling dead weight and not allowing weight for your load. I use a 5 x 8 trailer with a wire mesh floor from Northern Tool- https://www.northerntool.com/shop/tools/product_200671883_200671883
Its light weight plus works well but load it to anywhere close to 1000 lbs and I have found you will be dropping into 3rd gear at 55 mph 3500 rpm going up 6% inclines. I would spend your money on a new lighter weight trailer.

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I had to laugh at this. I went from a 5x10 Big Tex 30SA (which weighs 720 pounds empty) to a Big Tex 5x14 60PI (which was custom built to my specifications). The 60PI weighs 1200 empty (confirmed by a CAT scale) and the tandem axles took some getting used to, but backing up and traveling, I feel things are more secure.

It's a farm trailer, so I primarily bought it to pick up feed and supplies.

The heaviest trailer I've towed was a 70-PIX, but that's also 83" wide and it's rather precarious towing that thing (though I had to run to East Texas to pick up some things). With my Mk4, I got about 23mpg and a top speed of 70mph.

Weighing in on this thread, asking about trailer brake controller on my 2000 Golf. I recently got a camper trailer, and despite it not being very heavy (1700 dry, 2600 max), it does have electric brakes. So I figured I paid for them, may as well use them. Although the Golf seems to have no trouble stopping it (I do have upgraded 288mm fronts). I also have experienced trying to keep the speed down towing cars coming down long grades, and the extra axle's brakes would be a welcome addition.

I just am curious where you tapped the brake pedal signal wire to go to the controller. I purchased a Draw-tite unit, and am making up my own harness. Going to use a 30A self resetting circuit breaker for the main power feed. Couldn't find a nice plug 'n play Euro type trailer harness so I am making one of my own from a [Dodge] Sprinter kit as I now need the 7-pin round connector instead of the 4-pin inline.

I've only ever installed brake controllers on domestic (Ford) trucks that already had a connector for them.

What about tapping in to the pinouts of the rear light assembly for a low amperage wire to control a relay between a new fused power supply to the brake controller, does that sound like it would work?

Except the brake controller is up front. But the brake lamp signal is taken from the connector provided by Volkswagen in the tail lamp assembly.

That is the plug I was speaking of, but it is a long way to thread wire. I would most likely run a fused heavy as necessary gauge wire from battery or keyed power To the controller with a relay in it so as to not overload the circuit I am grabbing signal from. Perhaps the brake light switch could handle operating a relay without pulling too much current? I am interested in what you end up doing

The brake controller's "load" comes from a large feed through a 30A circuit breaker, generally directly off the battery. Since there is not any more slots to make use of in the underhood fuse link box on top of the battery, I'll be going directly from the post, and I may try and place the circuit breaker in the extra spot in the electric coolant heater relay box up on the firewall, just to keep it clean and tidy and out of the way.

The signal wire is just that, a non-load signal to the controller that the brake pedal is pressed. But I know sometimes if you try and tap into the brake light switch directly even that can cause the ECU to spaz out, but that would be the obvious place to go.

Since I will already be running a big power wire from the front to the back anyway (for the main brake power feed as mentioned above, and the main power to the lighting relay tree), I could certainly run a wire from the brake lamp output back forward but I may just find that lead up front instead and try that first. And that was my question, if anyone had already done so and where did they tap in.

When I installed the brake controller on the Tiguan I ended up using a relay to trigger the brake light input. It was several years ago, but as I recall the Tig electronics didn't like having the controller wire tied directly into the brake light circuit. I think it kept triggering the brake light out lamp. However, with the relay everything gets along fine. On the Touareg there is a wire up under the dash for the brake light signal, that makes it easier to install, no such luck on the "lesser" VW's. I'm not sure how the Golf is wired, but on the Tiguan I installed the trailer wiring controller, it plugs into the factory harness in the back. The 7 pin harness connects to the controller. You can set the parameters with vagcom and the US style combined turn/stop lights work fine.

I installed a Redarc brake controller. They don't recommend using a relay on the brake wire, but I have had no issues with it. In fact, I use this same controller on everything I have that tows a trailer. On the VW's I removed the dash light knob (I just connected the wires as I keep it at full bright anyway) and installed it there. It looks reasonably factory, at least it doesn't stand out.

The A4 cars are too old for the fancier CAN-bus tied in brake/trailer light controller, or at least they do not make use of them the same way. They just have connectors plug into the sockets in the tail lamps (that are already there). Not exactly sure where they are powered from. The knee-jerk way would be to tap into the 12v power socket supply, but that is not sufficient, or at least not for my setup. Not using a simple solid state module, I am using a bank of relays. I've bench tested all that, and that is all good.

I think I am also going to use a branch of the main battery power to go through into the trailer to keep its 12v battery charged up while travelling. It already has a diode installed so it cannot drain the car's battery when the engine is not running.

oilhammer said:

I think I am also going to use a branch of the main battery power to go through into the trailer to keep its 12v battery charged up while travelling. It already has a diode installed so it cannot drain the car's battery when the engine is not running.

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Yep, I did that as well. Full 7 pin harness, with two 10 or 12 gauge wires running up to the front, one for trailer brakes and one for battery charging. Not sure what's in the camper, but it should charge the battery when connected to shore power. But it doesn't hurt to have it charging when towing as well. I'm sure you are on top of it, but I had to install towing springs to handle the trailer tongue weight. We were using the Tiguan to tow a 17' Casita.

Not a lot of equipment in the camper, and it does have a built-in charger when on shore power. But the radio and lights and furnace are all 12v. Furnace obviously is not running when moving, but the radio seems to have a very slow draw over time, so for the time being I am keeping a regular 12v trickle charger/maintainer on it, until I can get the shore power outlet box installed on my house.

I put J-wagon springs in the back of the Golf, VR6 springs in the front, with Billy shocks/struts (for same application as the springs). So as you can see in the pic, it sits pretty good when loaded. The Golf's shorter overhang is more tolerant of tongue weight than the Jetta. I've also already had the larger front brakes on it.

Trailer dry weight is 1700, loaded (gross) weight is 2600. So well within the car's 3300 pound hitch. However, the shape of it obviously makes it aerodynamically challenging above about 50. But the Golf actually pulls it quite easily.

oilhammer said:

Trailer dry weight is 1700, loaded (gross) weight is 2600. So well within the car's 3300 pound hitch. However, the shape of it obviously makes it aerodynamically challenging above about 50. But the Golf actually pulls it quite easily.

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Sounds like you have the Golf dialed in. Just a note on camper weights. Typically the manufacturer listed empty weight is, shall we say, rather modest. I'm told they are usually weighed without propane tanks, battery, spare tire or most anything you could unbolt. Plus your camping equipment adds up quick. If you have it weighed, you might be surprised. The Tiguan did fine pulling ours, the only thing it didn't like was starting off on a good uphill incline. And no, we don't really have those in Florida, but we did go to the Smoky Mountains a few times. The Touareg is a much better tow vehicle, but I guess that is to be expected.

The big weight adders are bathrooms. This camper has none. And it isn't a pop up or slide out or any of that nonsense, so nothing there adding weight.

It does have a 30 gal freshwater tank (for the little sink in the rear kitchenette area), and of course the 30 pound propane tank.

We went with this one specifically because it was light, it was not a "soft side" so we can camp in bear country, it does NOT have a bathroom/toilet, and it has a full sized bed that does not require you to step outside of the camper while getting out of bed. We looked at the little teardrop ones and my wife said she didn't want to have to get out of bed through a door on to the ground.

I do some ATV riding, too, and this was a nice size to pull behind my F150 when I have the Recon in its 8ft bed.

For what a T'reg would cost, I'd just have kept my Sprinter and turned that into a camper. We'll see how the Golf does on longer trips, but the couple short (less than 25 miles) I have done with no trailer brake controller and my cobbled together manually operated trailer lights didn't give me much pause for concern other than if I hit some severe crosswinds at higher speeds. I've actually towed quite a bit with this Golf over the years, usually my utility trailer full of all kinds of things (scrap, my ATV, lumber, firewood) as well as quite a few broken Volkswagens via tow dolly. It has never let me down.

And it actually pulls hills with a car hooked behind it easier than my F150 does. Go figure.

When I added the controller to the JSW TDI I just tapped the black and red wire to the brake switch. Some would add a relay in the circuit, but I did not.
I did add the trailer module for the late JSWs but the problem is that the module I had did not have the NAR option in the setup and I had to add some resistors and a switch to activate the module.
VW makes no allowances for adding the electric brakes to most of their vehicles as the Europeans have been using (mechanical) surge brakes for some time and at one time basically outlawed electric brakes!
The Touareg does have provisions for adding the electric brake controller and is the only one I am aware of (well now the Atlas).
The TDI will pull the trailer (I have a 3000 lb Scamp 16') just fine, but it would be nice to h=be able to add a light duty weight distribution hitch.
I got 25 MPG with the 2013 TDI JSW.
I get 20 MPG with the 2012 Touareg, but it extra burn is worth is as it is much more capable and comfortable.

Yes, very strange they do not trust electric brakes, but trust hydraulics. I had an old trailer used with an old truck years ago that had that setup, and it worked OK but it would seem something easy to neglect (fluid) and it did eventually have a leaky wheel cylinder that needed attention. It was also somewhat clunky to adjust as I recall.

My Sprinter got 24 MPGs with 3000 pounds of Golf hooked behind it Of course, aero was likely a non-issue as the Golf was nicely tucked in the big van's slipstream.

oilhammer said:

Yes, very strange they do not trust electric brakes, but trust hydraulics.

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Not all surge brakes are hydraulic. We had a Rice Horse Box (that would be a horse trailer to us yanks) years ago. They are an English made horse trailer. At the time, there was a local company getting them CKD and assembling them over here. Anyway it had mechanical (drum) surge brakes on all 4 wheels. As long as you kept after the adjustments it did very well. I actually bought a wrecked one and made a great utility trailer out of it. This was back in the early 80's. Even back then they had 4 wheel torsion axles, etc.

I would guess the European hydraulic brakes work much better than the typical US setup. The Europeans take towing very seriously and the laws are pretty strict on what you can and can't do. Plus the vehicles towing them need trailer brakes to really work as they don't typically have a Diesel dually 1 ton pickup to tow with. I would say the European trailers match the vehicles. In the US we use brute force, over there it's more finesse. But then again, we don't have $6.00 or more per gallon fuel cost to contend with.

One more thing. If you really catch the camping and travel bug, you may eventually end up like us. 36' motorhome with 3208 Cat. 6 MPG is about it. It now tows the Tiguan on a trailer. I guess the Tiguan came full circle.

We also have driver's licenses that are much too easy to obtain, let alone keep, and very little enforcement if you don't know how to drive.

I'm into camping, not "glamping". I'll never have anything giant like that. The only reason I even got this little trailer is because Westfalia campers like I used to have are now a cult following and command far too much money than I am willing to spend on something that old and cantankerous. I like my old busses (I have a '79 T2 and an '82 T3) though.

Normally I've just tent or van camped, but I miss having some sort of dedicated camper due to the ease of last minute planning. I can decide on my way home Friday to go away for a quick weekend getaway if everything is more or less ready to go inside of 30 minutes.

This is what we camp in, gas hog not a diesel, but it is great for dispersed camping. I have a 3 way isolator to charge the camper, truck, and whatever I need to tow with batteries. approx. 15 gallons of potable water with electric and manual pump, 2 burner lp stove, and I removed the suburban furnace and replaced it with a wave 3 catalytic heater. gave up tents ten years ago when I bought this, sets up and goes down in minutes. We have travelled all over the state, gets in and out of most places and is pretty comfortable

oilhammer said:

We also have driver's licenses that are much too easy to obtain, let alone keep, and very little enforcement if you don't know how to drive.

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Amen to that!

For most of the year it's just too hot down here to camp without A/C or maybe we are just soft in our old age!
I never say never. We use to joke about the Casita being the smallest camper at the campsite. A friend of mine had the Wanderlodge for sale and we ended up with it. Actually in a few years we plan to spend months, maybe longer on the road so having something bigger will work out.