won't start no cranking. after a while it starts normal. What's the fix on 2005 Chevrolet Silverado 2500 HD

first occurred 2 weeks ago, I replaced battery and it still won't crank occasionally. Most times it works normally. there is a delay between turning key and engine cranking now when it does work. dealer said it would be hard to diagnose because it happens so sporadically

Asked by for the 2005 Chevrolet Silverado 2500 HD
if it wont turn over when you try and start it check small purple wire at the starter to see if you have power there when you try to crank the engine you will need someone to turn the key while you check for power if there is power but wont turn over then you have a starter problem