Won't Start

[mcoleman]

Everything acts fine in the run position but as soon as you turn the key to start you hear a click out under the hood and you loose power throughout the truck until you disconnect the batteries and then reconnect them. 1st thought in my mind was solenoid so I pulled the starter and inspected the solenoid. The Larry B kit still looks new. I then bench tested the starter and it engaged and ran fine. My next guess was the ignition switch on the column so I picked up a new one and replaced that last night. As long as you just turn the ignition to run you can crawl under the truck and start it by shorting across on the solenoid but as soon as you turn the key to start it clicks and kills power to the cab until you disconnect and reconnect the batteries. Is there a relay under the hood besides the starter relay in the fuse box that I've swapped out already that could be causing these issues? I was planning on checking all of the battery grounds to the engine this morning and maybe even try hooking up jumper cables to see if it was a bad battery or connection. But everything on the truck acts perfectly normal until you put the ignition switch into the start position.