Red On-Off Wire: Join this to the original blue coil power wire. Mount it so its insulated from ground and the coil feed. You can use a bolt and spade connection as shown in the photo - these used to come with MSD 6A and 6T boxes. You can leave the ballast resistor and connections for easy return to mopar box or make a new 4 way connection on an insulated stude. Either way the on/off wire will get power whenever the ignition switch is in either run or start. This draws very little power - just enough to turn on an internal switch in the MSD.
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Here's the instructions from my 6T. Hooks up the same, just written and illustrated differently.
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