When I hit the brakes on my 98 Monte the light in the rear view window works, but the tailight brake lights do not work. I replaced the tailight bulbs and the brake lights did work for awhile. Now they don`t work again. Only the light in the rearview window works. The bulbs in the tailight assembly are new bulbs. Only installed them a week ago.Any suggestions? I thought maybe the part by the actual brake pedal might be the problem. It`s driving me crazy.....Bob

 

Wont be the switch because the third eye ( back window light ) works. Grab a test light and start from the socket and start working backwards until you find the bad spot.

 

Turn signal switch is the most likely cause. I have replaced quite a few turn signal switches for this on 95-99 Monte Carlo's.