What could make a 1996 Dodge Dakota crank sometimes and not others?

I bought a wrecked 1995 Dodge Dakota. (Its not that bad. Just the right fender and light) It will crank once and a while but most of the time it wont crank at all. It always turns over though. The fuel pump is fine and so is the ignition coil. It got hit on the side where the computer is so I'm wondering if I need to replace that. Can anyone offer their opinions? Thanks so much.|||check all your connections at the battery, the main pos to the starter and your grounds first. ps. to mechanics cranks and turns over mean the same NO offense|||sounds like a lose connection|||You may have a winding out on the starter motor