95 Transport Door Lock Problems

When the van is in gear and I touch the break all of the doors unlock, when I let off the break they all lock. Any ideas

Hello I actually have a 95 transport with that exact problem. It first started with the passengers side window not wanting to go up when the button was pushed. the drivers side works great. Then with the window problem came fuses always blowing for the horn. Now when i drive sometimes my doors will lock and unlock when i push the brake and let go. Very strange, i am also looking for the problem any ideas?

MOst probably a ground or 12v splice problem. Take a chance to investigate condition of floor under driver and passenger side carpet. Several weird conditions have been reported due to corroded splices under carpet.
DO you have an automatic load leveller?