Dagu Trex controller not put energy to the motors

I guys, im very new on arduino, and is the first robot i build, i buy the dagu wild thumper 6/6 and t-rex controller, i use lipo battery 7,4 v 5700mah.

When i make the all connections and put my rx and link the battery i no ear any beep from motors, i check with multimeter and the 4 pads go to motors no have any value.

I try put battery directly on the motors conection and the motors work, and the t-rex work also.

On the normal way the voltage enter on the t-rex controller but not going to the motors.

Whats happen with is ?

 

Many thanks for the help