north for short,
Isolate the problem, Remove the MD12 & check the camera for operation. If it's a meter problem replace the camera battery(MS76's). When reinstalling the MD12 be sure both camera & motor are cocked. There was a sync problem with the MD11's that Nikon cleared up with the 12 but you never know.
Oh yeah when the bodyis separated from the motor you may need to pull the advance lever away from the body to activate the meter.