Sounds like the unit is making the connection, though outgoing power needs to be checked. It sounds to us like there is a unit problem since the refurb, that the power supply is not providing positive current.
Though it seems that the unit is getting a communication.
The ground activates the lights, and is monitored by the unit for the SS system to work.
There should always be a hot positive (+) in the boxes to the lights. That is where we would check first.
Good Luck!
BCB