US Shift 4R70W Installation And Operation Manual page 20

a -2.5V to +2.5V signal instead of 0V to 5V. To make this signal work, install the
provided 10µF, 25v, non-polar, electrolytic capacitor inline between the
speedometer output of the Quick 4 and the device that it is driving. To install the
capacitor, cut the speedometer output wire and solder a capacitor lead to each
of the two cut wires.
Tachometer Signal Input:
The tachometer input can be connected to a digital tachometer output from an
engine computer or the tachometer output from an MSD ignition or similar CDI
(Capacitive Discharge Ignition) system, but NEVER to the coil outputs of a CDI
system like MSD. For breaker points (or conventional electronic ignition systems
such as GM HEI, Ford Duraspark or TFI), it can be connected to the coil
negative terminal. For COP (Coil on Plug) ignition systems that do not have a
conventional tachometer output (such as later Mustang engines), one of the coil
trigger wires can be used, but the update rate will be slow. A better approach for
such applications would be to use a tachometer adapter such as the AutoMeter
9117.
Overdrive On-Off Switch:
The Overdrive switch can be used to turn overdrive on or off. The switch can be
a latching switch (toggle switch, latching push-button, etc.) or a momentary type
switch (spring-loaded push-button switch, spring-loaded toggle switch, etc.)
connected to +12v ignition-switched power and pin 4 (brown) of the vehicle
harness. (The tan wire on pin 12 is for VSS output and shouldn't be confused
with the brown wire on pin 4 for the O/D switch.) A momentary switch is needed
to use more than 2 states. Optionally, you can add an O/D indicator lamp
between +12v ignition-switched power and pin 2 (white) of the vehicle harness.
This lamp will normally light up when overdrive is off. Also, without adding a
switch, a single-click of the controller's knob can turn overdrive on and off. This
setting can be configured under the "Flex-Shift" tab of the tuning software.
Whenever the O/D or manual state is changed, it will be scrolled on the
controller's display (O-d On, O-d Off).
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