1996 Outback 2.5L

Problem: Car on, brake engaged, can't depress gear shift button to move out
of park.

So far - took apart the center console to see the mechanism that stops the
shifter from going down if the brakes aren't engaged, it's not moving out of
the way even though the brakes are engaged.

I can manually move it with my hands and get the car in gear, but I need a
permanent solution.

Possible cause? I've been having odd electrical problems - my battery is
corroded and the ABS light comes on intermittenly, the fan for the heater
sometimes stops, and the universal door lock doesn't always work. These
problems are never permanent.  Could this whole gear shift thing be related
to the system thinking the brakes aren't working?

Any suggestions? Thanks in advance.