Syren 50 and pixhawk orange

Hi I bought this SyRen 50A regenerative motor driver
(SyRen 50A regenerative motor driver - analog, R/C, and serial motor control)

When following the manual I think i did everything right but i cant seem to get any response from the motor ive connected ( an old underwater scooter motor brushed 300 watt ) I know the motor works, and everthing else I connect on the RC ports work, servos x3 and a ESC with a thruster on it. This Syren and motor are connected to channel 3 ( throttle ) and if i put the thruster on this pin nr 3 it works perfectly

Have I misunderstood the SyRen 50 manual? I have adjusted the PID as pr the manual, any help is much appreciated

Rune

SOLVED. needed to connect ground to the syren also. Awesome costumer service at www.dimensionengineering.com