This ought to get you where you need to go:
Click Here

Putting a diode in-line on the #1 wire will keep voltage flowing in only one direction (towards the alternator) and insures against engine "run-on" -- you can buy a 4-pack of diodes from Radio Shack for only $3 or $4: Part #1N4001

~~ Alan Horvath
1954 Chevy Pickup
Singing his praises in the
Passing Lane