Don’t read any further if you would prefer to leave the Touareg’s trailer braking control as a mysterious puzzle. Attached is the schematic for the 2006 Touareg trailer wiring.
The areas outlined in dashes are where the 7-pin trailer connection and brake controller get added. First, you can see that the brake signal to the brake controller comes from the Towing Control Module (J345). This is shown in column 10. The brake controller output is delivered directly over to the 7-pin connector. Note there are more pages to this which show more inputs and outputs into the Towing Control Module. This schematic has a number of implications:
r If the Towing Control Module has an anti-sway function, it would send a brake signal to the Brake controller when sway is detected by the stability control module. If this happened, you would see the brake controller light up without hitting the brakes.
r A system like MaxBrake that takes it’s signal from measuring brake line pressure could not get the anti-sway control function
r The brake controller sees the real current to the trailer brakes, there is nothing in the way so what the brake controller measures is real
r There was no good reason I can see for CAN or other low level signals to be on the brake signal line. The brake controllers were made by both Hella and Westfalia so this might explain why some have this problem and some don’t
r Since the anti-sway control (if there) would work by sending a signal down the brake signal before you apply the brakes, for the anti-sway control to work one needs to have some level of “boost” set on the controller to send something to the trailer when there is no deceleration.
r The LED problems looks like the J345 controller just being confused by the trailer LEDs low current. The ZVW 808 004 kit probably solves this by some resistors to ground to draw more current.
Other points:
r Whoever said the 000 979 228 wires recommend by Tekonsha are too small was technically right. The schematic shows the wire gauge in mm2. The Red/Yellow wire with power is sized at 4mm2. It should not be connected to a 2.5mm2 wire. Why? Wires should be sized to carry all the current available until the fuse blows. In other words, the fuse should blow before the wire melts. Is this likely? No, you would have to have a fault in the brake controller that allowed high current, but not high enough to blow the fuse. Not a likely situation. You should use the heavier wire from the 000 979 302 kit, but you really only need it to terminal 2.
r I checked the schematics for 2007, 2007 Tourareg 2, and 2008 Touareg 2. All of them show a similar setup with a brake controller connector. So the design team looks clean on this one, if you have the towing package and no connector, it is a defect. If you have the J345 controller in the back with wires coming off to brake controller connector, likely the connector is somewhere in the car but you may not be able to get to it
The areas outlined in dashes are where the 7-pin trailer connection and brake controller get added. First, you can see that the brake signal to the brake controller comes from the Towing Control Module (J345). This is shown in column 10. The brake controller output is delivered directly over to the 7-pin connector. Note there are more pages to this which show more inputs and outputs into the Towing Control Module. This schematic has a number of implications:
r If the Towing Control Module has an anti-sway function, it would send a brake signal to the Brake controller when sway is detected by the stability control module. If this happened, you would see the brake controller light up without hitting the brakes.
r A system like MaxBrake that takes it’s signal from measuring brake line pressure could not get the anti-sway control function
r The brake controller sees the real current to the trailer brakes, there is nothing in the way so what the brake controller measures is real
r There was no good reason I can see for CAN or other low level signals to be on the brake signal line. The brake controllers were made by both Hella and Westfalia so this might explain why some have this problem and some don’t
r Since the anti-sway control (if there) would work by sending a signal down the brake signal before you apply the brakes, for the anti-sway control to work one needs to have some level of “boost” set on the controller to send something to the trailer when there is no deceleration.
r The LED problems looks like the J345 controller just being confused by the trailer LEDs low current. The ZVW 808 004 kit probably solves this by some resistors to ground to draw more current.
Other points:
r Whoever said the 000 979 228 wires recommend by Tekonsha are too small was technically right. The schematic shows the wire gauge in mm2. The Red/Yellow wire with power is sized at 4mm2. It should not be connected to a 2.5mm2 wire. Why? Wires should be sized to carry all the current available until the fuse blows. In other words, the fuse should blow before the wire melts. Is this likely? No, you would have to have a fault in the brake controller that allowed high current, but not high enough to blow the fuse. Not a likely situation. You should use the heavier wire from the 000 979 302 kit, but you really only need it to terminal 2.
r I checked the schematics for 2007, 2007 Tourareg 2, and 2008 Touareg 2. All of them show a similar setup with a brake controller connector. So the design team looks clean on this one, if you have the towing package and no connector, it is a defect. If you have the J345 controller in the back with wires coming off to brake controller connector, likely the connector is somewhere in the car but you may not be able to get to it
