Need Help

[miller502]

Hello, I have a 2005 Gmc crw cab 1500 Z71 and every light on my truck flickers at certain times. The lights wont totally go out they just flicker real fast. Sometimes it does it and sometimes it doesn't. My volt indicator shows 14 at idle and goes slightly higher when accelerating. The lights flicker like a police cars headlights only not as noticeable. I don't have a clue where to start. Thanks

[DofD]

Is there any particular situation where the flickering is likely to happen? Like when driving a certain speed? Does it do it when the truck is just sitting idling? Does the flickering happen when the truck isn't running? That is with just the dome lights on in the cab.