91 s10, 4.3L. Drove fine yesterday. Went to start it today, engine turned once, didnt start, wouldnt turn again. Tried to start again, heard a click, still no start, didnt turn this time. Tried to jump it, after turning the key a few times, trying to start it, the power shut off.completely. no dash lights, headlights, radio. Nothing. Zero reaction from anything at all when trying to start the truck. Test light to battery lights up when connected, in-cab fuses are all good, not sure how to test PWR/PWR ACC relays. Any opinions?

 

a test light will light up on a almost dead battery - pull battery terminals and clean well - my 84 did about the same thing - couldn't jump it - dead power inside - side post terminals were corroded inbetween cables and battery - cleaned them up well and lubed them and battery with copper coat, no problems since