What year is your Touareg? My 06 needed a headlight control model.
Had differing issues with headlights for several months and they finally went dead. Period.
Went to a locally highly experienced and recommended VW repair service. After replaceing all bulbs, with new ones and 1.5 hrslater it was discovered that part of the problem was in the light/turnsignal shaft on the left side. There was a short. So a replacecment part was gotten from the Dealer, and after 3 hrs, 3 technicians, it was found that the replacement part was defective.
But I do have head lights on the d river side but none on the passenger side. Going next week again to have the new replacement part installed. Has anyone else had that issue? Could there be a TSB on this?