My alternator went bad. So I bought a new battery to be able to drive the truck temporarily. I wasn't paying attention that the posts on the new battery were on opposite sides as the old one. When I hooked it up backwards, it fried my starter. I just replaced the starter and the alternator. My lights and everything like that works. But the truck still won't turn over. I checked the starter with a screwdriver. It's fine. What could be the problem?