Lionel action cars

I was given an operation milk car and the “action track”. The action track has a wire harness that goes straight to a control box with two buttons. I inserted the action track into my lay out and placed the milk car on the track. When I pushed the buttons on the controller nothing happened.

My question is should there be a wire that runs from the control box to the transformer or isn’t that necessary?
Beatle

The track and controller should have four wires. No others are needed but track power must be on and the slide shoes on the trucks must be on the power rails. Check the underside of the car to make sure the wires are still soldered on.