MSD 89501 RPM Activated Switch, DIS Installation - Manual (Page 2)

2 INSTALLATION INSTRUCTIONS
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Figure 1 Operation of the RPM Activated Swtich.
WIRING
Red Connects to a switched 12 volt source.
Black Connects to ground.
White The rpm input wire. With an MSD Ignition, this connects to the Tach Output terminal.
On inductive ignitions, it connects to the coil negative terminal.
Yellow This is an activation wire and is Normally Open and will switch to ground. It connects
to the ground side of the device you plan to activate.
Gray This is an activation wire and is Normally Closed to ground. It will open the ground
path of a circuit.
MOUNTING
The Switch may be mounted under the hood as long as it is away from direct engine heat sources.
Keep in mind that the rpm modules should be easy to access for changes. The Switch can be
mounted with the double-sided tape or with the four self tapping screws supplied. Use the Switch
as a template and mark the mounting hole locations. Remove the Switch and drill the holes using
a 3/16" drill bit then install the screws.
Figure 2 Wiring to a 4-Cylinder, Coil-per-Cylinder Ignition.