YotaTech Forums - 93 Toyota 4x4 22re - Strange Electrical Problem(s)

93 Toyota 4x4 22re Extra cab, -
When following my son in his truck on a rainy day, we noticed that his brake lights did not work. This is what we observed when we got to where we were going.

Brake lights work when head lights are off
Brake lights do not work when head lights are on

As an aside we have also noticed

Dashboard illumination lights stay on when truck is turned off, until foot is removed from brake pedal, then they go off.
Tail lights are dim

All other lighting (turn signals, etc.) seems to work fine.
Any thoughts on where to start and what to do?
And help is much appreciated.