Installation Instructions for SUM-830450-1
Summit Racing RPM Switch with Digital Readout
* Always disconnect the battery
before
attempting any electrical work on your vehicle.*
WIRING INSTRUCTIONS
Note: Automotive circuit connectors are the preferred method of connecting wires. However,
you may solder if you prefer.
Note:
If doing an LS motor swap, pick up the tach signal wire from the ECM/ECU and then set the
tach switch to 4-cylinders.
MOUNTING INSTRUCTIONS
Power
-
Red
Connect to a sw12V source.
Ground
-
Black
Connect to an engine block ground.
Tach Input
–
Grey
Connect to the negative terminal of your coil, or, if using a high energy CD
ignition, connect to the tach output of the ignition system instead.
Tach Output
-
Blue
Connect to your desired RPM activated device.
Note: If the device to which the blue wire is attached draws more than 3 amps, a relay must be
used to drive that device or damage to the unit will occur.
Warning:
If using this switch with a multi-coil vehicle, you must attach the switch’s GREY
tachometer input wire to the tachometer output on the PCM and set it for 4 cylinders.
If your vehicle has a
separate ignition coil
, connect the gray wire to the
negative
(-) side of the
coil – the wire that goes to the points or electronic ignition module.
If your vehicle has a
GM HEI ignition
, connect to the terminal marked ‘TACH’, or, on some
systems, a single white wire with a spade terminal.
If your vehicle has an
after-market ignition
– some systems will connect to the TACH output
terminal.
If your vehicle has a
computer controlled ignition
system, consult the service manual for the
wire color and location.
If your vehicle has a
magneto
system, connect the tach signal wire to the negative side of the coil.
Do not
connect the tach terminal to the positive (+
or
high voltage) side of the ignition coil.
