MSD Module Selectors
Two Step, PN 8739
Three Step, PN 8737
Parts Included:
1 - Module Selector
4 - Mounting Screws
1 - Parts Bag, Wiring Terminals
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 corresponding 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.
ACTIVATION WIRES
Module 2
This is the default module. It is active when no voltage is present
on the other wires.
Module 1
Active when 12 volts are applied to the Red Wire.
Module 3
Active when 12 volts are applied to the Blue Wire. (3-Step Only)
Note: If 12 volts are applied to the Red and Blue wires at the same time, Module 3
will be active.
TO MODULE SOCKET
MICRO SWITCH
PN 8820
SWITCH OR
TO 12V
RED
STEP
MODULE SELECTOR
TM
PN 8739
TO LINE LOCK
OR TRANS-BRAKE
SOLENOID
AUTOTRONIC CONTROLS CORPORATION
1490 HENRY BRENNAN DR, EL PASO, TX 79936
BLACK
MODULE 2
MODULE 1
TO GROUND
Figure 1 Basic Two Step Module Selector Installation.
AUTOTRONIC CONTROLS CORPORATION • 1490 HENRY BRENNAN DR., EL PASO, TEXAS 79936 • (915) 857-5200 • FAX (915) 857-3344
2
INSTALLATION INSTRUCTIONS
REV LIMITER
STEP
MODULE SELECTOR
TM
PN 8739
RED
BLACK
AUTOTRONIC CONTROLS CORPORATION
1490 HENRY BRENNAN DR, EL PASO, TX 79936
MODULE 2
TO
GROUND
JUMPER
CLUTCH
SWITCH
TO
GROUND
NO
87
86
87A NC
30
(+) 12V
85
MOMENTARY
PUSH BUTTON
SWITCH
C
RELAY
PN 8961
(+) 12V
MODULE 1
LINE LOCK
SOLENOID
IF YOUR APPLICATION REQUIRES USING THE CLUTCH FOR EVERY SHIFT,
THIS DIAGRAM WILL PROVIDE A REV LIMIT ON THE LAUNCH ONLY AND
HOLD THE LINE LOCK ON UNTIL THE CLUTCH PEDAL IS RELEASED.
TO
GROUND
Figure 2 Wiring a Two Step to a Latching Relay.
MODULE 2 - ACTIVE WITH NO VOLTAGE.
MODULE 1 - ACTIVE WITH 12 VOLTS ON RED WIRE.
MODULE 3 - ACTIVE WITH 12 VOLTS ON BLUE WIRE. THIS
MODULE WILL ALSO BE ACTIVE IF 12 VOLTS
ARE SUPPLIED TO THE RED AND BLUE WIRES.
C+
CRPM
GROUND
IGN
T PTS
A
C M+
H
M-
TO 12V
3
TO LINE LOCK
OR TRANS-BRAKE
SOLENOID
MODULE SELECTOR
TM
MODULE 3
RED
PN 8737
AUTOTRONIC CONTROLS CORPORATION
1490 HENRY BRENNAN DR, EL PASO, TX 79936
MODULE 2
BLUE
TO 12V
CLUTCH SWITCH
MSD MICRO SWITCH
PN 8820
MODULE 1
BLACK
TO GROUND
Figure 3 Basic Three Step Installation.
AUTOTRONIC CONTROLS CORPORATION • 1490 HENRY BRENNAN DR., EL PASO, TEXAS 79936 • (915) 857-5200 • FAX (915) 857-3344
INSTALLATION INSTRUCTIONS
WHITE WIRE
TO POINTS OR
AMPLIFIER
IF USED
3
TO MAGNETIC
PICKUP
TRIGGER
IF USED
TIMING COMPUTER
PN 8980
BLUE
SWITCH +12V TO ACTIVATE
THIRD RETARD
RED
SWITCH +12V TO ACTIVATE
SECOND RETARD
BLACK
THIRD
RETARD
MODULE 3
3
MODULE SELECTOR
TM
PN 8737
AUTOTRONIC CONTROLS CORPORATION
1490 HENRY BRENNAN DR, EL PASO, TX 79936
MODULE 2
MODULE 1
PN 8737
WHITE
BLACK
(NOT USED)
TO GROUND
BLACK
FIRST RETARD
WHEN GRAY WIRE
IS GROUND THERE
IS NO RETARD, OPEN
SWITCH TO RETARD.
FIRST SECOND
RETARD RETARD
GRAY
GRAY
RED
MAGNETIC
PICKUP
(NOT USED)
TO BATTERY
WHITE
RE
D
YELLOW
IGNITION KEY
+12 VOLTS
+
HEAVY RED
+
HEAVY BLACK
TO BATTERY
OR
BLA
TM
N
IGNITIO
AN
GE
CK
COIL
AUTOTRONIC CONTROLS CORPORATION
PART NO.
SERIAL NO..
Multiple
Spark
Discharge
TACH OUTPUT
Figure 4 Wiring a Three Step to a Timing Control for Multiple Retards.
SHIFT LIGHT
3
MODULE SELECTOR
TM
MODULE 3
PN 8737
THIRD
SHIFT POINT
PN 8737
AUTOTRONIC CONTROLS CORPORATION
1490 HENRY BRENNAN DR, EL PASO, TX 79936
MODULE 2
BLACK
MODULE 1
BLACK
FIRST
SHIFT POINT
SECOND
SHIFT POINT
TO GROUND
RED
GREEN
BLUE
SWITCH +12V TO ACTIVATE
THIRD SHIFT POINT
RED
SWITCH +12V TO ACTIVATE
SECOND SHIFT POINT
TO SWITCHED
12 VOLTS
TO
TACH OUTPUT
Figure 5 Wiring a Three Step to a Shift Light for Multiple Shift Points.
AUTOTRONIC CONTROLS CORPORATION • 1490 HENRY BRENNAN DR., EL PASO, TEXAS 79936 • (915) 857-5200 • FAX (915) 857-3344
TECH NOTES
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Service
In case of malfunction, this MSD component will be repaired free of charge according to the terms of
the warranty. When returning MSD components for service, Proof of Purchase must be supplied for warranty
verification. After the warranty period has expired, repair service is charged based on a minimum and
maximum charge.
Send the unit prepaid with proof of purchase to the attention of: Customer Service Department,
Autotronic Controls Corporation, 12120 Esther Lama, Suite 114, El Paso, Texas 79936.
When returning the unit for repair, leave all wires at the length in which you have them installed. Be
sure to include a detailed account of any problems experienced, and what components and accessories
are installed on the vehicle.
The repaired unit will be returned as soon as possible after receipt, COD for any charges. (Ground
shipping is covered by warranty). All units are returned regular UPS unless otherwise noted. For more
information, call the MSD Customer Service Line (915) 855-7123. MSD technicians are available from 8:00
a.m. to 5:00 p.m. Monday - Friday (Mountain Time).
Limited Warranty
A
utotronic Controls Corporation warrants MSD Ignition products to be free from defects in material
and workmanship under normal use and if properly installed for a period of one year from date of
purchase. If found to be defective as mentioned above, it will be replaced or repaired if returned prepaid
along with proof of date of purchase. This shall constitute the sole remedy of the purchaser and the sole
liability of Autotronic Controls Corporation. To the extent permitted by law, the foregoing is exclusive
and in lieu of all other warranties or representations whether expressed or implied, including any implied
warranty of merchantability or fitness. In no event shall Autotronic Controls Corporation be liable for
special or consequential damages.
AUTOTRONIC CONTROLS CORPORATION • 1490 HENRY BRENNAN DR., EL PASO, TEXAS 79936 • (915) 857-5200 • FAX (915) 857-3344
FRM22502
Revised 03/01
Printed In U.S.A.