MSD 8950 RPM Activated Switch Installation - Manual

IMPORTANT: Read the instructions before attempting the installation.
Parts Included:
1 - RPM Switch 4 - Heat-Shrink Caps
4 - Self Tapping Screws
Note: RPM Modules must be purchased separately. See the chart on the last page for part numbers.
The RPM Activated Switch can be connected to stock ignition systems or MSD Ignitions. When using a
capacitive discharge ignition such as an MSD, do not connect the Switch to the coil negative terminal.
Damage to the Switch may occur.
The Switch is capable of carrying 1.5 amps. If the circuit you are activating requires more current,
an MSD Relay, PN 8960 or 8961 must be used. The MSD RPM Activated Switch is equipped with a
"smart driver". This circuit will protect the RPM Switch from damage by monitoring its temperature.
If there is an inadvertant short or too much current is drawn through the Switch, the smart driver will
sense the increased temperature and shut the Switch off. However, once the temperature drops to a
safe point, the smart driver will turn the Switch back on. It will continuously cycle On and Off as the
temperature dictates.
If you experience a problem with your Switch not operating, turn the circuit off for a few minutes to cool,
then try again. If the circuit activates then shuts off, there may be too much current flow. Check the
device's Installation Instructions to find its recommended maximum current.
The RPM Switch has two activation wires. The Yellow wire is Normally Open and will activate a circuit
by switching to ground. The Gray wire is Normally Closed to ground and will open the ground circuit
at the desired RPM (Figure 1). If no rpm module is installed, the Switch will not activate the circuit.
Figure 1 Operation of the RPM Activated Switch.
M S D
• W W W . M S D P E R F O R M A N C E . C O M • ( 9 1 5 ) 8 5 7 - 5 2 0 0 • F A X ( 9 1 5 ) 8 5 7 - 3 3 4 4
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MSD RPM Activated Switch
PN 8950