Blown fuse
Your brake light switch under your pedal is brobaly stuck
There are two of them, which one? Instrument cluster - parking brake on or low brake fluid Overhead console - brake pads need to be replaced.
Our manual shows f24 as brake light fuse
I was looking at the 1999 Mercury Cougar Owner Guide and it does not show that it has a gas cap warning light
On a 2000 Mercury Cougar : That's your Anti-theft system status light
Your brake light ignition switch should be replaced. It works your brake lights and ignition switch, so you do need it. It only costs about $7 dollars.
1999 Mercury Cougar brake light bulb lamp replacement: Purchase the correct replacement brake light bulb(s) first, before disassembling the vehicle. See sources and related links below for replacement brake light bulb information. Then consult your owner's manual for the replacement procedure. As simple as it sounds, the owner's manual is the best place to start for brake light bulb lamp replacement instructions and illustrations. You may want to consider replacing both left and right at the same time in order to keep brightness and color equal (optional).
On a 2000 Mercury Cougar : The OIL PRESSURE warning light is located on the right side of your gauge cluster just above the red " BRAKE " warning light It looks like an oil can Just before you start the car , when the ignition key is turned to the RUN position , the light should light up for a few seconds to prove that the bulb works
You need an oil change.
You are low on coolant.
it is located on the light a switch that says 12sec on and off
'P'arking or emergency brake