Why can't I move the gear shift out of park?

The brake lights work, but, when the pedal is depressed, there is no movement from the shift lock solenoid. I checked the voltage to the solenoid and it is very low (barely readable). What should the voltage be going to the solenoid? If I know what voltage it will accept, I can jump it to see if it even works. Is it possible for the brake pressure switch to be bad even if the brake lights work? Or, is there another relay or switch between the brake pressure switch and the Shift lock solenoid? If yes, where is it? Information about this car is difficult. A spec manual would be a great help, but, I have not been able to locate one. Any help you can offer would bve greatly appreciated.