all lights on vehicle blink very rapidly, battery light on and volt meter showing 13-14 volts. Battery will be dead after a couple of weeks of driving. Dealer is diagnosing faulty battery cables (both) for $639.00. Has anyone had this problem solved with battery cables?

 

I would think the cables are a good bet, after that the alternator.
They put the extra battery slot in that? Might be worth tracking down all your connectors and checking for corrosion/loose nuts.
4.8 is cherry! I bet your getting some killer mpg's out of that.

Welcome to the forum

 

I have an 07 avalanche with the 5.3 that get 2-4 mpg better Thanks Matt B for the reply and I will be changing the cable set today

 

$639.00?! I was not paying attention. Simple bolt on parts.You can buy both for $100