Hi my air flow selection switch not working proparely every time i turn on the heat weather i put it on panel vents or floor vent the only thing that truns on is the defroster vent what do you think is the problem here its 2006 ford f 350 6.0 diesal

Just got 07 transit swb and none of the roof lights work in side

Its going to be one of two thins either the blend door is broken or the gears in the blend door motor are stripped happens often these little motors only stop once the door is closed or open but i think the timer is offten too long causing them to break the blend door or strip the motor,remove the glove box and watch them work,they are easy to remove once off you can open them up and inspect the gears,usually the one connecting to motor worm gear is stripped out. good luck