which light is it? brake light for e-brake? abs? hope you aren't driving with it on. don't know if mechanic caused this to come on or if it just happened to be correct timing of a problem with it. If you took your car to jiffy lube I am not surprised. Jiffy lube has been in trouble for not doing the work ordered on a car and also causing problems. I had to take my car in a quick lube place because we are military and needed prove of residency so I could keep my out of state tags. Everytime I went there they said there was some major problem wrong with my car. These guys are not professionals and are not qualified for these types of repairs. They said 2 of my cars both needed a rear main seal. They unhooked my intake and didn't put it back, then said I needed a new fuel filter (which I put a new one on months before that). Take it to a mechanic that is qualified to have them diagnose it. Sometimes you can make a claim against jiffy lube saying that they caused this if you can get another shop to say that it was.
A dashboard light appearing when brake pedal is depressed usually means brake fluid is low.
Is it the parking brake light or the ABS light? is it red light or amber?
If the light is on your dashboard it would be the Anti-lock Brake System
To indicate a problem with the brake system.
Low brake fluid in master cylinder? Parking brake not fully released?
Which light are you asking about? Dashboard location would help -- Brake lights mean the brake is being applied, but I'm sure that's not what you're asking.
Check the brake light switch, it's under the dashboard, connected to the brake pedal.
...I have the exact same problem with my 1993 corolla.......Brake System warning light and discharge warning light
Most likely it is either the brake light switch, under the dashboard, connected to the brake pedal or the turn signal switch inside the steering column.
Problem with the anti-lock brake system. Take it to a pro. I would try replacing the brake light bulb in the high brake light located in front of the rear window. If the bulb is blown this will also make the cruise control not work, and the ABS light will come on from it. I am not sure if this is true for all of the brake lights or not, but it is worth a shot before seeing a pro.
in the brake fluid reservoir usually located under the hood. If you are unfamiliar with this are as it sounds you are I would take it to a local jiffy lube or mechanic where they have some idea about what to put in and where to put it.
Brake light switch defective or out of adjustment.