Hi all,

I have a 2007 Q7 4.2, and have developed an electrical issue when towing my utility trailer. When plugging in the trailer, the Q7 senses that the left rear light is out, and disables the brake lights. The brake light out caution then displays in the dash, and I have no brake lights. Last year when I towed, all worked fine. The trailer works fine on other vehicle. A new trailer I hooked up today to the Q7 produced same symptoms. The hazards work, as do turn signals and night running lights when hooked up to the Q7. The only thing different from last year is that the right most rear backup sensor was replaced a few months ago.
Anyone have any suggestions? I'm stumped on this one.

Tyler