If the only thing that goes in the back is the dog why don't you get a doggie seat belt. Most vet's, pets or $2 shops I've seen have them. Leave it plugged into the buckle and just unhook it from his collar when it's time to get out. I use them and the sensor thinks it's the standard belt instead. Plus keeps Rover to his seat instead of landing in someones lap if the worst was to happen .