Help with a 1970 GMC Sierra Grande

[BiocidaLRay]

Im new here but check it out, i have a 1970 GMC Sierra Grande, i need some help, first i would like to ask, Where can i get a Wiring Diagram for my truck? and i dont mean to buy one, can someone send me a photo or a link to a website that has diagrams pictures, the problem i have is that i have to charge the battery every time i go to start it up, now check it out my battery works and its new, my alternator works and its new too, my voltage regulator is new, my starter works, ok now check this, today i went to the store and my lights were brite, my flashers were brite, my brake lights were brite, now i was driving and i got to the store, picked up the stuff i needed, i didnt kill it, i left it runnin went it got the stuff, got back in the truck and left, when i was driving home i noticed my lights were not as brite as the were before, i pulled into my driveway, got out, looked at the lights, and i noticed they were dimm very dimm, like they were about to go out, my friend got out and started looking at them too, before we could open the hood, the truck died, NOW LISTEN, i got back in the truck turned the lights off and turned the key in the off postion, then i turned the lights back on with the truck turned off, the lights were shining as brite as the sun, and so was the dome light and the flashers, and the brake lights keep in mind thats with the truck turned off, then i turned the lights off, and then i tried to turn the truck on and it wouldent even turn over, i dont understand what is going on, could someone help me out please?

Thanks

[sherman69]

I'd clean the battery cable connections and retighten them. Also where the cables bolt to. such as the ground connection.
Bob B

[BiocidaLRay]

thanks but i just fixed it yesterday, come to find out my truck is a "Frankinstien" Truck, i had a new alternator on there but it was a 1970 alternator with external voltage regulator, BUT what i didnt know was that when my grampa left it to me, he had changed it to the alternator with the voltage regulator inside the alternator, so i replaced that 1970 alternator without the VR inside of it, for a 1978 alternator with the VR inside, and re wired some stuff and it started right up no problems