There are a few different problems that can cause this problem, the first is the brake switch, check and make sure your brake lights are working , there is also a interlock control unit that can cause this problem, the third thing is the relay on the shift solenoid on the shifter, these are the most common problems with the interlock system the only easy fix would be the brake switch, let me know if you have more questions, ROY!
Roy, does the interlock control pull the solenoid to ground, is that how this circiut is controled? My diagrams are crude, yet I believe I have made enough sense of them. I dont believe i am getting that ground. The brake lamps work, also.
Here is the interlock electrical system power comes from the switch to the control unit to the solenoid , Thanks ROY!