Having issues with my 98 B2500 not starting. When I first put the key in all the electronics come on. Turn the key to start and everything go dead! Have to remove battery cables to get everything back. Battery in new and was checked, have new starter installed today and the ignition relay checks out good! Any help would be thankful.

 

I would bet anything that the problem is with the battery cables internally. The battery may have leaked in the past which deteriorated the cables inside the plastic insulation. You cannot see this from the outside.

I have seen this so many times. It causes a voltage drop when putting a load on the battery and everything goes dead.