go to Auto zone and ask them to check your codes its free
The brake light switch is located on a bracket behind the brake pedal support.
Remove the light assy with the mounting screws.
there are screws on the top and side of the light. They use torx screws. there are screws on the top and side of the light. They use torx screws.
Stuck brake light switch.
Check the brake light switch, it's under the dashboard, connected to the brake pedal.
Bad bulb, corroded socket, or loose or disconnected wiring.
All 1995 and later model vehicles require an OBDII scanner tool to retrieve the trouble codes.
I can help you I had that problem on my 1988 cutlass ciera and the answer is that one of the lights on the back not the third small on is not working. Open the trunk take out the bulb itself and check the wiring. That what was wrong with mine someone didn't have it wired right. Hope this helps you out.
how to installing a turn light switat in 1995 Oldsmobile ciera
service engine does not have to be on. unless battery has been disconnected, all codes should still be in memory and you will be able to retrieve the codes. I had the same thing happen in my 96 cutlass, it was throwing a code every now and then. The service engine light would come on for a while then go away, however, the car did idle roughly but drove smoothly, after putting the code reader on I found that the cam positioning sensor was faulty. I replaced the sensor the car idled smoothly and the code went away. Hope this is helpfull to anyone.
You may want to consider replacing the thermostat.
I think the only way to get to it is to go inside the trunk. You will see the wires going up to it. Then after you losen it then you go back in side the car to change it.