I drove for about 3 hours tonight, and about every 5 minutes (not exactly), my headlights turned off (could here the relays ticking), immediately turned back on, followed by a single chime. The dash illumination also brightened (since the lights went off) and then dimmed. happening more often, and more randomly, was just a chime. None of these symptoms have ever occurred, and I don't think I have changed anything on the truck that would cause it all of a sudden... its weird.

I haven't ever read about this issue, so I apologize if its already been answered, but does anyone have any idea whats going on?

thanks