I have a 1995 Mercury Grand Marquis and my mother has a 2003 and they both are the same, so yours probably is also. After you pull the trunk lining away so that you can see the metal, there are 3 large black plastic wing nuts that you unscrew. Once you remove those, the tail light section will come out from the front and then you can get to the bulbs to replace them.
You don't. The switch is all one , you will have to replace the entire switch.
i got the same problem with my 99 Audi a6.
On a 2000 Mercury Cougar : That's your Anti-theft system status light
I was looking at the 1999 Mercury Cougar Owner Guide and it does not show that it has a gas cap warning light
You need an oil change.
You are low on coolant.
it is located on the light a switch that says 12sec on and off
Blown fuse
its below freezing temperature
I have a instrument light that is on ---- 1999 Cougar , it looks light a transmission, but I think it is the emission indicator on the far left of the steering wheel, what does this mean?
Check and fix the engine.
The radiator fluid is low or you parked the car at am angle.