Don't feel bad I did the same thing with a no start, However on my behalf, I cleaned the terminals with a wire brush first (apparently not good enough), so I looked at everything else down to the resistance on the ground wire two starters and two battery's later I was still wondering why it would only start with the jumper hooked up. Turns out that the reason it would start with the jumpers is cause it was on the out side of the terminals. But looking back on it that's what makes this stuff fun. Or maybe I'm just sick.

89 V6 manual trans Dodge Raider frame 87 cold weather pkg 2" body lift, Soft 8's wraped in BFG km2 33x10.5x15, JDM Pajero yellow Bosch fogs. Yackama basket. Duel bouncies gen II rear springs,gen II ft brakes,master and booster.