MSD 8956 Window RPM Activated Switch Installation - Manual

IMPORTANT: Read the instructions before attempting the installation.
Parts Included
1 - RPM Window Switch
4 - Self Tapping Screws
Note: RPM Modules must be purchased separately. See the chart on the last page for part
numbers.
The RPM Activated Window 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 Window Switch has a circuit that activates a device by providing a ground path at a desired
rpm (Figure 1). The ground will be removed at a different rpm to deactivate the device. If no rpm
module is installed, the device will remain activated as long as the rpm is above the activation amount.
Figure 1 Operation of the RPM Window Switch.
4 - Heat-Shrink Caps
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 Window Switch
PN 8956