Remote control's battery bay issue, no voltage at the end of circuit
If all the batteries are fresh (make sure you test before putting them in) then its probably an issue with the battery terminal. Either the terminal contacts are eroded from batteries being in there too long or the battery terminal has become detached from the circuit board.

If its eroded terminal contacts then I suggest wiping away any loose erosion and then using a small amount of vinegar to clean contacts.

If its a faulty connection you will need to take apart the controller. To fix, solder the battery terminal back to circuit board.

Edit: The battery terminal was detached and had to be reconnected