1997 Chevy Venture dimm break lite

Not much information to go on Joshua.
However, have someone to apply the brakes while you look at the brake lights. Now turn on the ignition switch and a signal light and apply the brakes. What happens?
If the lights tend to something funny (on goes off and another comes on, or all on at the same time), then that means that the tail light circuit boards are bad and need to be replaced (they will show signs of overheating).
If you have to replace the circuit boards, check the electrical connector which goes to the boards. If they show signs of overheating, replace the connector as well (sold at the GM dealer).