My blower motor for my heat, and a/c doesn't blow. When it did work when you turned the fan off with the a/c on the light for the a/c went out. Now no matter what position the fan switch is in the a/c light stays on. Is this a problem with the blower motor or resistor or is it the switch?

SOURCE: 2004 Dodge durango-blower not working

the blower is the same for front and rear. you have a blend door problem look by your feet on drivers side just under dash there is a slide mechanism that breaks.

SOURCE: blower motor not working

If you are mechanically inclined and have patience for first time projects.The blower motor should be up under the dash behind the glove box,some are enclosed with the heat and ac and require dash removal,I know this from Dakota trucks but I am not 100% for the newer vans.It might also be under the hood on the passenger side firewall.
In any case it usually involves removing cosmetic panels and unless you know where the screws and clips are it will take time to find them or you could do what one of my friends did and use a crow bar but his van doesn't look so good anymore RedGreen would be proud of the use of duct tape.

SOURCE: 1999 Dodge Ram 1500 Fan Motor Resistor Location

I've never seen a vehicle w/o a blower resistor. You don't need to remove the blower. The resistor is about 2 inches x 3 inches and is installed in a hole in the plenum (duct) near the blower motor. It will have a wiring harness connected to it. It could be under the passenger dash or under the hood, depending on where the blower motor is.

SOURCE: Location of the rear blower

The blower motor resistor gets very hot, so it is always located in a position where the blower can keep it cool. Inside the box with the blower but accessed from the outside, usually with two screws holding it in.

SOURCE: 2004 dodge heater blower motor dead. Motor,fuse. relay ck good

most likely that is the problem