Ok, another weird one. (00 F150 4X4 5.4) Every now and then I'll be driving around, and things start flashing. Basically the spedo and stereo lights flash from bright to dim. While this is happening, you can hear a relay ticking, just like a turn signal. On the outside of the truck, it appears the hazards are flashing. Usually it will keep this up for a minute or two, then go back to normal. Any ideas?