:is the classic sound of a weak battery. Can you try another battery? Be sure your connections are clean to your starter too.
I took the battery out and put it in my 08 Frontier and started right up no problems. When I try to start it the relay in the drivers side fenders starts clicking but nothing else. The lights on the dash go off,not sure if they are supposed to do that. I guess Ill go crawl underneath and clean everything again and see if that helps. I just did this swap and cleaned, painted everything so there is no reason why this should not start. CAn you thing of anythign else? is this a grounding issue?>