On my 99 f150 i have a factory single disc cd player. Lately all the speakers keep cutting out when i hit bumps. I pulled the deck out and inspected the wires, and they look ok to me. There are 2 harnesses on the factory setups, but one of the harnesses doesnt seem to do anything. The main harness is tight in the connector, and when i wiggle the harness around the speakers dont cut out. It seems to be only when i hit bumps in the road. I tried another factory deck and it does the same thing. Only the speakers cut out, the deck doesnt shut off, and it happens on both cd and radio. I'm stumped. Has anyone came across this before?

 

Take the door panels off, and check to see if the speakers are connected good