8

INSTALLATION INSTRUCTIONS

BALLAST RESISTOR

If you have a current trigger tach (originally coil

positive) and use the White wire of the MSD,

you can purchase a Chrysler Dual Ballast

Resistor (used from 1973 - 1976) and wire it

as shown in Figure 5.

ENGINE RUN-ON

If your engine continues to run even when the ignition is turned Off you are experiencing engine Run-

On. This usually only occurs on older vehicles with an external voltage regulator. Because the MSD

receives power directly from the battery, it does not require much current to keep the unit energized.

If you are experiencing run-on, it is due to a small amount of voltage going through the charging lamp

indicator and feeding the small Red wire even if the key is turned off.

Early Ford and GM: To solve the Run-On problem, a Diode is supplied with the MSD in the parts bag.

By installing this Diode in-line of the wire that goes to the Charging indicator, the voltage is kept from

entering the MSD. Figure 6 shows the proper installation for early Ford and GM vehicles.

Note: Diodes are used to allow voltage to flow only one way. Make sure the Diode is installed

facing the proper direction (as shown in Figure 6).

Ford: Install the Diode inline to the wire going to the #1 terminal.

GM: Install the Diode in-line to the wire going to terminal #4.

Figure 6 Installing the Diode to fix Run-On.

GM 1973 - 1983 with Delcotron Alternators

GM Delcotron Alternators use an internal voltage regulator. Install the Diode in-line on the smallest

wire exiting the alternator (Figure 6). It is usually a Brown wire.

1A-400V DIODE

TO CHARGING

LIGHT

SPLICE HERE

OR

DELCOTRON

ALTERNATOR

FORD VEHICLES

ATTACH DIODE TO

TERMINAL "1"

EARLY GM VEHICLES ATTACH DIODE TO TERMINAL "4"

1

2

3

4

SMALLER OF THE 2-WIRES

DIODE

WIRE LOOM

GM 2-WIRE ALTERNATORS

FROM POINTS

OR AMPLIFIER

MSD WHITE

MSD RED

SWITCHED 12V

(original coil+ wire from tach)

CHRYSLER DUAL

BALLAST RESISTOR

Figure 5 Wiring the Dual Ballast Resistor.