Same deal here - but it's my driver's side that flickers when the juice is low. A relatively new battery is unlikely to be the cause of your issue, but it wouldn't be the first time I've heard about a DOA battery. It also doesn't eliminate the possibility of a charging system issue. The check the battery, put a meter on your battery and crank the truck over, watch for the voltage to drop significantly. To check the charging system, let the truck warm up and meter the battery, you should see about 14v.