I have a 2005 Peterbilt 335 with a Cummins 8.3, when I turn the key,, nothing,,does not turn over,,just some clicking. I boosted the batteries thinking they might need help, made no difference. It first did it after a hundred mile run and after it cooled down it started just fine. Yesterday I started it and moved to the fuel pump and shut it off and then no start. When it does start the starter sounds fine and it fires right up. I guessing it is a bad connection or possibly an electric relay. Does this ring a bell with anyone? Thanks