Why does my blower for the heater keep going off in my astro van?

I have the same problem in my vehicle. It boils down to either two things, the climate swiches or the wiring on the blower. I'd bet it's the latter. Turn your heat on high and wiggle the cover for your fan (it's on the penger side under the glove box and is somewhat round in shape) if it comes on you have a loose connection and just need to take the cover off and secure the terminals.