Was driving down hwy, 97 Gmc sierra 5.7, complete loss of power followed by just 1 click when I try to start it ....help me please! Anyone had this happen?

sounds like the battery cables need cleaned and tightened. they have a weird washer setup on it and are very touchy. if not that post back and we may have to get into ign switch or relay trouble shooting

Ok I'll check it after work again, but I already loosen and tighten battery connections, and they have a clean contact, I also tried to jump the truck off my buddies diesel, still no luck.

If jumping it didn't get you restarted, I'm suspecting a bad battery. How old is your current battery?

Less than a year old,

Yeah to me it sounds like the battery shorted out. I would try swapping it with a known good one before changing any parts.

I agree with Shaun. I've seen batteries fail just months after being put in.

Ok thanks I'll let u know...

Still just a click, engine not even trying to turn over.

you check the other sides of the battery cables, and the grounds? the big engine ground will make it quit and not restart. if those are good and clean, you will have to test the little wire for 12v when key is in run and trace it back