12 volts need to be added which are active upon pulling the gear switch. The solenoid is then active and unlocks the lever.
A minimum of 12V (up to 28V) can be used on the solenoid. 5v supply for the integral backlight and gear down warning.
Thank you to Simon for the schematics and pinouts.
x/w Solenoid (12-28v)
p/r Integral backlight (5v)
s/t Gear down warning (5v)
l/a Gear down (connect to your I/O interface). There are multiple redundant gear down connections.