MSD Ignition 8739 Installation Instructions

Parts Included:
1 - Module Selector
4 - Mounting Screws
Note: Do NOT use solid core spark plug wires with any MSD component.
The MSD Module Selectors provide the ability to switch between two or three different rpm or
degree modules. The different modules are activated when 12 volts are applied to the correspond-
ing activation wire. The Selectors work with either a Soft Touch Rev Control or any MSD Timing
Control that uses plug-in modules.
•The 2-Step Module Selector switches between two modules.
•The 3-Step Module Selector switches between three modules.
Module 2
Module 1
Module 3
Note: If 12 volts are applied to the Red and Blue wires at the same time, Module 3
will be active.
MICRO SWITCH
PN 8820
SWITCH OR
TO LINE LOCK
OR TRANS-BRAKE
SOLENOID
AUTOTRONIC CONTROLS CORPORATION
MSD Module Selectors
Two Step, PN 8739
Three Step, PN 8737
ACTIVATION WIRES
This is the default module. It is active when no voltage is present
on the other wires.
Active when 12 volts are applied to the Red Wire.
Active when 12 volts are applied to the Blue Wire. (3-Step Only)
TO MODULE SOCKET
TO 12V
RED
TO GROUND
Figure 1 Basic Two Step Module Selector Installation.
• 1490 HENRY BRENNAN DR., EL PASO, TEXAS 79936 • (915) 857-5200 • FAX (915) 857-3344
1 - Parts Bag, Wiring Terminals
BLACK
STEP
MODULE SELECTOR
TM
PN 8739
AUTOTRONIC CONTROLS CORPORATION
1490 HENRY BRENNAN DR, EL PASO, TX 79936
MODULE 2 MODULE 1