I posted this about a year ago, but got no concrete answers, hoping someone else has run across this since. All my lights, dash, headlights everything pulse. It used to come and go but getting worse now. I have had it in the shop numerous times and different shops, but no one has been able to find the problem. Everything seems to think its a ground problem but they have checked every ground they can find and no luck. Battery has been changed twice, alternator checked numerous times and it puts out steady voltage. Pickup is a 2005 GMC Sierra Denali with 99,800 miles. It has NO aftermarket products at all, nothing has been added anywhere on the truck. Any ideas?