my 80 toy is killing the battery, the charge light is on and the motor runs down till it is dead. The alt checked good at the parts store and the external reg has been replaced. Any ideas? Please help.

 

The voltage regulator needs to have a good ground at the base to work. Scrape it shiny. If the alt. bench tested ok and the regulator is new, there may be somthing wrong with the wiring or fuses in the truck. Check every fuse in the truck for blown ones. Check the battery volts with it running. Should be 13.8. If so than it is charging and somthing is turned on.

Which should not be much in an '80. What I do when that happens is start taking out fuses. If you have an amp meter that you can hook into the positive cable it would help. There are no ECU's on an '80 so there should be 0 (parisitic) drain in the battery except the radio memory. (A few milliamps) Also check behind the radio. If it has a memory power and a key power wire ( usually red and yellow) they should not be connected together. I find a lot of people doing this wrong on much older trucks that were not wired for modern raidos.

I have had the charge light get stuck on those before. Dont pay too too much attention to that.

 

here's exactly what is happening. Jump start the truck and the charge light is on. After a few seconds the charge light goes dim and then out and truck dies. The truck runs very rough during the latter half, even barely alive with my help feathering the gas.
I will go look for fuses and try the amp meter today. I didn't work yesterday 'cause it was so damn windy and cold. Hey it isn't my truck, just trying to get a friend on the road when he comes back from out of town.

 

Let me know what turns up.