B6 Passat Towing

[passatpout]

OK, here's the scenario:

I towed the boat from Melbourne to Echuca (and return), all up about 450km of towing.

I'd rewired the boat lights, with new lights, new cable where needed, and IP65 rated junction boxes. Attached it to the car, tested, everything fine.

After about 5 minutes of driving each time, the warning light regarding trailer lights comes up, and the next time I turn the ignition on (is that the right term with a diesel?), warning messages come up, alternatively telling me:

"Trailer brake lights not functional".
"Trailer tail lights not functional"
"Trailer left hand tail light not functional".

So this has left me with a couple of questions:

How is the 12 (or 13)-pin VW plug wired? Does it have a separate feed for both sides of the tail lights, with only the RH one used with the 7-pin converter?

Why would it intermittently come up, after verifying that the trailer lights are working and without breaking any connections?

Is it worth taking it back to the dealer to get checked out?

Nothing that I thought was too bad, just annoying to have the light on when not needed, and reducing the chances of actually picking up a genuine fault.

[rotelman]

Hey Passatpout,

I just got my passat last week. I have the VW installed Tow bar. I towed my Bike trailer last weekend. Worked fine without any problems. I'm in Melbourne so if you wanted to try out a different trailer send me a PM and we can hook up.

Whilst having the trailer on last weekend I discovered that the electric tail gate wont operate at all. I took it to VW where I bought it, after some phone calls and discussions behind closed doors, I was subsequently told that this is a "Safety Feature".. Safety for what? I asked. I said that I was not happy with this response and have asked them to contact VW Germany to find a solution. The only way I can open the tail gate is to force it open manually or un plug the trailer!
The other thing I noted was that the reverse sensors should turn off when the car is hooked up to a trailer....welll so you would think??

Anyone with a E tail gate and tow bar with the same problem?

Rotelman.

[passatpout]

Oh yeah, that was the other thing.. it didn't turn off the reverse sensors when the trailer was plugged in.. good fun going up and down a boat ramp (can't see the trailer without the boat on it, so lots of to-and-fro-ing), having to hit the button every time.

I'm a bit miffed about it, for the cost of the bar you'd expect it to be hunky-dory.. but having checked out Euro wiring diagrams, they do feed both side tail lights independently, and if the adaptor here only feeds from one side, it'll fault every time.

[vanDub]

The other thing I noted was that the reverse sensors should turn off when the car is hooked up to a trailer....welll so you would think??

Can't help with the auto tailgate issue as I have a sedan but the reverse sensor turning off only applies to "factory fitted towbars" ie the european ones. Our towbars and associated electrics are "dealer fitted' and are essentially after market items made by Best Bars in NZ. The sensors don't turn off when the trailer is connected but you can do it manually via the button on centre consol.

What is the ball download on the boat/trailer assembly and how did the Passat handle it?

I am curious as the Passat supposedly has a 85Kg download limit (90Kg in the supplement but my supplement only applies to 103Kw diesel). I can understand part of their reasoning as the rear sinks down markedly with rear seat passengers or a load in the boot (10 bags of pool salt had the rear mudflaps scrapping 98% of the time)

[tryingavw]

I am curious as the Passat supposedly has a 85Kg download limit (90Kg in the supplement but my supplement only applies to 103Kw diesel). I can understand part of their reasoning as the rear sinks down markedly with rear seat passengers or a load in the boot (10 bags of pool salt had the rear mudflaps scrapping 98% of the time)

don't these cars have auto levelling rear suspension?

[passatpout]

Can't help with the auto tailgate issue as I have a sedan but the reverse sensor turning off only applies to "factory fitted towbars" ie the european ones. Our towbars and associated electrics are "dealer fitted' and are essentially after market items made by Best Bars in NZ. The sensors don't turn off when the trailer is connected but you can do it manually via the button on centre consol.

Well, I'm going to let them know that for $1500 I'm expecting something with a few more smarts in it. Besides, if it's not factory fitted for trailer wiring, then why would it still have a Euro-style round 13-pin plug on the car?

What is the ball download on the boat/trailer assembly and how did the Passat handle it?

It's quite light - total mass of boat and trailer would be around 400kg loaded, and it's balanced just slightly towards the front, so estimate ball download of ~45kg. Was just enough to notice the load on the towbar pushing the rear suspension down when first hitched up. More suspension play when the boot was loaded up with suitcases, clothes, etc.

One day I'll take the car and trailer to my local friendly weighbridge and do total mass as well as download on the jockey wheel.

I am curious as the Passat supposedly has a 85Kg download limit (90Kg in the supplement but my supplement only applies to 103Kw diesel). I can understand part of their reasoning as the rear sinks down markedly with rear seat passengers or a load in the boot (10 bags of pool salt had the rear mudflaps scrapping 98% of the time)

I'm guessing the reason for the low download limit is to keep the front wheels on the ground. The more they lift off, the less adhesion and the more likely they are to spin. The effect of the ball download in lifting the front wheels increases the greater the distance between the rear axle centreline and the tow ball centreline, and it's a fair distance from axle to towbar on a Passat wagon.

[MrBean]

Passatpout,

You are right about keeping the front wheels on the ground. I have 1400kg boat/trailer and last week changed my Commodore Berlina for a new Passat 125kw wagon with a dealer fitted towbar. Generally it's ok towing the boat except for standing starts which have to be slow and gentle otherwise the front wheels just spin due to loss of traction. I have looked into this and was advised to fit a load leveller but there is waring in the handbook not to do this. I therefore intend to move the trailer axle to reduce weight on the hitch. Another option is fitting air bladders inside the rear coil springs but these have to be inflated when towing and deflated when not towing - a pain in the a*se.

I find reversing down a boat ramp easier than with the commodore as I just reverse with the tailgate open an can see everything.

I have the same problem with warning lights re trailer lights and would be intersted in possible solutions.

[Caddyman]

Hi, I have a dealer fitted towbar(bestbars) and the reverse sensors turn off when a trailer is connected, it even comes up with a grey picture of a trailer a frame on the reverse camera screen. And my auto tailgate won't open when it is connected, you can open it manually then.

Matthew

[PA.]

Rear Parking Sensors should automatically turn off when the trailer plug is in. Front still works.

Power Tailgate should not work by default as there would be a possibility that the trailer may be in the way. By making you get out of the car and manually open it would reduce the chance of damage occurring as the tailgate crashes into your Jockey Wheel or Boat Winch. I know my old boat trailer winch would foul the rear door on my Subaru.

Seem to remember there may be an option in the MFD to turn on/off the rear sensors when the trailer plug is in.

[Umai Naa!!]

For those whose rear parking sensors aren't turning off with the trailer attached, have the dealer rectify this. They've not programmed the whole shooting match correctly when they've fitted the trailer electrics.

In regards to the lights issue, nine times out of ten, it's a fault in the trailer's wiring. Also, if you're using LED lights on your trailer, that will also cause issues.

As for the auto tailgate, if the trailer plug is connected, or the reverse sensors have picked up something, it will not open. It's no different to Eos roofs not working when an object is within range of the reverse sensors. It's just a safety limitation.