Possible electrical problem on 89 Silverado

I have an 89 silverado with the 350. My problem is anytime I use the right turn signal and sometimes the left the truck totally dies, losing all power. It may go 1-2 weeks without doing it and then it will do it several days in a row. Even on some occasion it will do it when I turn on the headlights. Anyone have any clues?

I had a similar problem. Would loose all electrical. I finally tracked down a short where the ground from the battery was attached to the inide of the fender well. Also check the wire attached to the hot side post clamp.(If you haven't already.)