Tommy, pull your back seat out and take the v-drive cover off. You'll see a white piece of pipe, that's your ballast manifold. There's three switches on it, I forget which way to set them but if the back two are filling and the front isn't then one should be set one way and the other two the other way. So set all three the way the single one was and you'll be set.
Your bag may not empty for a couple of reasons. One, the pump is not functional ( wiring, worn out, etc), also check that the hose that drains the bag is not kinked some place stopping the flow of water.