1991 cutlass supreme brake lights wont shut off

Probably not a fuse but a back up light switch.. very cheap part..

if the bulbs and fuses are okay then it may be the brake switch itself that is either bad or out of adjustment. it is located on back side of brake pedal on top, when brake pedal is pushed it pushes on switch to activate brake lights. have a good day !!

check voltage from brake switch to signal light switch, if good the the signal switch is probably bad

You probably have a bad brake light switch. This switch is located on the brake pedal arm or a bracket next to the arm. This switch activates the brake lights when the pedal is pushed. You can check this by turning on your turn signals or warning flasher if your light flash in the rear. Your bulbs are good so this will bring you back to the brake light switch.

Try having someone push on brake pedal at the same time thay move the turn signal lever up and down slightly to see if your brake lights work this would tell me that you have a faulty turn signal switch because GM runs the brake lights thru the turn signal switch so they work if you are driving with your 4way flashers on.

Change your turn signal switch in the steering column 99% sure that is your problem you can some times check by holding the brake pedal down and wiggling the the switch around and have someone watch to see if the come on

I have a 1987 Cutlass Supreme and the brake lights wouldn't work. When I moved the tilt steering to a certain position they worked.

the brake light issue is probably causing the shifter not to work because when you press the brake it tells the shift lock system to allow the vehicle to be shifted from park. If there is no power there it won't work and both systems usually work off of the same switch. if you check the fuse panel for a stoplamp or brake fuse it will probably be blown....replace it and your shifter will probably work once again as well.
hope this works for you....good luck!

check grids along rear window to check for broken lines and check wires on both sides of glass where connections are.

Hope this helps. contact me if you need more help please give me a rating if you would.