That is your " check engine",or the other name for it is On board diagnostics system.One of your emission control systems may be malfunctioning.It could be because of poor fuel or water in the fuel or the fuel cap may not be any good
You are low on coolant.
On a 2000 Mercury Cougar : That's your Anti-theft system status light
I have what looks like a battery light on my dashboard. What does this mean?
its below freezing temperature
Check and fix the engine.
On a 2000 Mercury Cougar : The warning light that looks like a can with an X through it , located between the engine coolant temperature gauge and the tachometer ( at the bottom of the gauge cluster ) is your ( LOW engine cooling system warning light )
it looks like a little orange engine in lower left on dash
Follow the troubleshooting tree that is associated with that code.
With an OBD2 scan tool. The problem must be repaired or the light will just come back on.
it is in the manual says when this happens it is 02 sensor and if it is flashing you have a miss in your engine which can cause damage.
I was looking at the 1999 Mercury Cougar Owner Guide and it does not show that it has a gas cap warning light
usually that the battery isn't taking a charge. have the alternator checked, many shops will test the charging system for free