MSD 7531 Programmable Digital-7 Plus Installation - Manual (Page 2)

2 INSTALLATION INSTRUCTIONS
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WIRING
Ignition supply wire. Connects to battery positive (+) terminal or battery junction.
Note: Do not connect to the alternator.
Ignition supply Ground wire. Connect to battery negative (-) terminal or engine block.
Red On/Off switch wiring. Connects to a switched 12 volt source.
Primary Coil Leads
Orange Connects to the coil positive (+) terminal. This is the only wire that makes contact to
the coil positive terminal.
Black Connects to the coil negative (-) terminal. This is the only wire that makes contact to
the coil negative terminal.
WARNING: High voltage is present at the coil primary terminals. Do not touch the coil or
connect test equipment to the terminals while the engine is running or cranking.
Green
2-Pin
Heavy
Red
Heavy
Black
PROTECTION
The MSD Programmable Digital-7 Plus has a built in reverse polarity protection circuit. This will protect the ignition
in the event of wrong connections. It will also shut off for protection from a surge in power. The ignition will still
operate once the surge or polarity is corrected.
LED INDICATOR
There is an LED that monitors the status of the Ignition. The LED will verify trigger inputs and will flash trouble
codes such as a Code 2-blinks for No Cam Sync or Code 3-blinks for Low Battery supply voltage.
CAMSHAFT SYNCHRONIZATION
This is used only in applications where the individual cylinder timing is going to be used. The 2-pin connector
with a Light Blue and Light Green wire connects to a sensor that is used to synchronize or alert the Ignition as to
when the number one cylinder is going to be triggered. With this information, the Ignition knows which cylinder
is being fired allowing for the individual cylinder timing capabilities. MSD offers two kits to use for sync signals:
Universal Cam Sync Sensor, PN 2346 and a Fiber Optic Inductive Pickup Kit, PN 7555.
Trigger Wires
Violet/ Magnetic pickup, 2-pin connector. Plugs into an MSD Distributor or Crank Trigger
pickup. Violet is positive, Green is negative. Note: When this connector is used, the
White wire is not connected.
White Trigger input for electronic ignition amplifiers, an ECU’s trigger or points.
Note: When this wire is used, the magnetic pickup wire is not connected.
Tach Output
Gray Tach output. This wire will provide the same 12 volt square wave tach signal as the
tach terminal on the side of the unit.