vtraudt

I was told the 13 pin connector that comes with our Allroad tells the car that a trailer is connected.

Does anyone know which of the 13 pins is used, and "how" to tell the car that a trailer is connected?

Is there a dash light for 'trailer'?
What is the car 'doing' with the information (change ride height? input to the ECU (cooling for example?). Other?

Here are the pins:

MrBye

Im my car (2001 2,5TDI) it puts the suspension in MAN, and turns off the parking aid sensors at the back of the car.
Might be more features, but that is all i know.

Tongboy

If you have a euro plug installed from the factory its not a pair of wires that signals the suspension and the reverse sensors - there is a switch installed in the plug that has an additional 3 wires that run to it that performs this operation.

if you pull the back of the rubber plug on the harness off you'll see the 3 wires.

it looks likes there is a normally open and a normally closed wire and as the switch is actuated it switches (similar to the way the brake switches work.)

I replaced the switch with a standard rocker switch so that I could wire in a 7-pin RV plug to replace the euro adapter (Or rather hide it in the bumper) I I mimicked the operation of the factory microswitch but so far it isn't doing anything other than 'normal' behavior - when I'm in reverse the the trailer sets off the reverse sensors and I don't think the suspension behavior has appreciably changed.


If you added the wiring harness as you have to with the earlier cars i've read that there isn't a microswitch and is instead controlled as part of the wires down the 13 pin.

vtraudt

Well, turning off the backup warning is already a nice feature. Worth looking further into it.

vtraudt

Well, my wires really don't seem to match what the factory manual says.

Here are MY wires. Can anyone decipher the colors to match the factory?
Most urgently: I need to find the 4 wires needed for a 4 pin flat connector BY TOMORROW (towing early Saturday morning):

http://i853.photobucket.com/albums/a...8-09200551.jpg
http://i853.photobucket.com/albums/a...8-09200557.jpg

Tongboy

well you can rule out your two browns as grounds

the heavier gauge wire should be either the charge or power supply constant 12v

now you only have 6 extra wires you don't need for a 4 pin.

of those 10 wires the only one that matches the audi published standard is the blue/red wire that is supposed to be pin 4/right hand indicator.

get out your multimeter and set it to 12v, turn on your right blinker and hook your multimeter ground to metal on your allroad and see if your multimeter reports a blinking voltage signal from that wire.

do the same thing with the left hand indicator - put your left blinker on and check all of your still-unidentified wires to figure out which one has the correct signal on it.

once you have the left/right signals down the other two get a bit more complicated. with the allroads ignition switch on go looking for anything that is constant hot or ground and rule those out. then get a board to hold your brakes down or a helper and go looking for the brake signal. then do the same with the parking lights on to find the parking lights signal.

vtraudt

Until I have figured out how to properly (built in car 'features' (like backup disabled, backup lights disabled, 'trailer' dash light, etc.) AND where to take the signal/wire for the electrical brake from, I have rigged up a simple flat 4 pin.

The 4 pins are:
1x left turn
1x right turn
1x light
1x ground

Where is the 'BRAKE' light wire going to?

vtraudt

Should I wire the brake light to left and right turn signal?
Will this blow up my cars electric system?

This seems to be the standard method for 'normal' (='tractors type') cars:

A green wire runs the right turn and brake lights. A yellow wire runs the left turn and brake lights. A brown wire runs the taillights. The white wire is the ground wire, and the red wire is the backup lights

Read more: How to Wire a Flat-Four Connector | eHow.com http://www.ehow.com/how_7892710_wire...#ixzz23RyDK4LX

JustMtnB44

You need the 3-2 tail light converter that I talk about in my wiring guide on allroadfaq. Most American cars already combine the brake and turn signals so that you don't need a separate brake wire. Since these functions are separate on the allroad, you need the converter to combine them together. I don't think much is going on in that converter, but it is slightly more complicated than just connecting them together because that would likely short something.