I have a 2007 Chevy wt I turn the key it makes a click and all the power goes off I wait a couple of minutes then the dome light comes on sometimes truck will start or may take 2 or 3 times it has died at a stop light than then had to wait for power to come back on acts like it has a multi breaker thought it was the starter until it died at the light help please not sure where to look

 

You might want to check all the connections starting right at the battery cables where connected to the battery. Be aware connections can look OK and yet have corrosion underneath. Looking at them does nothing. They would need to be removed , inspected , cleaned and reinstalled. It does sound like power to the vehicle is being interrupted.
AND,,,,,,,,, this includes ground connections too.