My brake/stop lights stopped working this morning when I got in the car. Worked last night when I parked it. Back up lights, turn signal lights, tail lights work fine. Just the brake lights don't work.

Fuses are all fine and I replaced the brake light switch last month.

The 3rd center brake light still works. It's just the two regular brake lights that are not working. Any ideas what could be going on?

Car is a '92 Firebird TransAm.

 

Yep. Your brake light switch is faulty. There are two sets of contacts in the switch, one set trips the main brake lights, the other set trips the 3rd brake light.

The switch is stupid simple. Pop off the cover and you can visually see how the switch operates. Have a look inside and you'll probably see what isn't making a connection. A simple adjustment might be in order too.

 

Mine melted the plastic rod inside once and it wouldn't open or close the circuit, I forget which now. Its really easy to replace. just remove the wires from the switch and pull it out of the bracket. When you put the new one in it just pushes all the way in.

 

Same problem. Just replaced my brakelight switch last month and the lockup converter also started working again. (only 240k miles, wish GM could make something that lasts lol)