Maybe a dual purpose light? I had a 95 Mach 1 that when you hit the brake the red light would come on as an indication the the brake light was working. Light would not come on when the tail light was burned out or removed. The red light was also an indicator that the oil level was low. Maybe you had a sticky brake switch when you first started it
. Just a guess but I think it may hold 10 galllons of fuel.
