[aircooled]

From one Airstream and Touareg owner to another:

Circuit teseters rarely work well on the Touareg. The Touareg needs to see a full lighting load to enable the charging circuit in the tow module.

Do this: Hook Airstream up. Have you (or dealer) measure the battery charge at the trailer battieries. Note the voltage. It should be in the 12-12.8 range. Now hook up the trailer umbilical to the running Touareg. Go back and note voltage at the batteries. It should be slowly increasing to 13.8-14.4V, indicating you have a charge. Make sure the trailer battery disconnect switch is in the ON (powered) position. Off will leaving you with no charge to the batteries.

Failing all of that, check the fuse from the vehicle to the trailer to see if it has blown.

 

[aircooled]

He's fine with a 23' both in length and weight. Let's not turn this into a towing discussion.

Laurence is probably right on PIN 4 always being on, at least on a T1/T2. I have no direct experience with a T3 and if the systems might have changed greatly in this design. I do remember that in the early T1's the fuse for the charge cable was not installed.

All of this bears asking: Is this the factory tow package?