We're assuming the trailer brake lights even worked. Maybe they didn't work and it never crossed the mechanic's mind. Who knows if the driver knows what a PTI is..........

I honestly don't remember the brake lights being on when I drove in but they may have been and I just didn't notice. He very well may have had a fuse blown or something there too! The "mechanic" like I said, had no idea what he was doing. I would have ran him off the first hour myself!!

But like someone else said, I've never driver off with the interlock engaged, or the pto running, or anything like that :)