The Rundle link posted by Gord is a little misleading. Not by Gord, but by Mr. Rundle (R.I.P.). He seems to indicate he "borned" the DA plug. The DA plug which stands for Delco Alternator was used by GM when they replaced the Delcotron (DN10) externally regulated alternator, with the 10si (System Integrated) internally regulated alternator in late 60's/early 70's.
The "plug" is a connector shell with female contacts. Rundle just took one of those and added wires and a diode to it for folks installing a 10si; and sold them.
The diode is not necessary if the ignition switch is wired properly to eliminate "run on". The feedback was never "thru" the AD ignition switch as he says, it was because the wire to the coil was not on a separate switch terminal from battery hot and therefore backfeed voltage stayed connected to the coil because the wires were on a terminal block style connection. Bypassing the switch internals.
On newer ignition switches, so called V8 switches, there is a "ACC" terminal, a good place for the alternator wire to attach.
The wire I'm speaking of is the 10si terminal 1, on a three wire install. This wire can go thru an idiot light on it's way to ACC or not.
As Gord says
ClickAND
THISRed to alternator stud, same place as batt hot...... and white to Ignition switch per above comments.
BY THE WAY, YOU KNOW WE ARE ALL TALKING 12V, RIGHT? 59 motor is 12V, So truck has been converted with bulbs, gauge voltage reducers, ballast resistor, etc?????????????
