Why is the horn honking and light flashing on my 2000 Lincoln LS?

My car did that when the battery died. I have a different kind of car, but it was because the car thought I was trying to jump start it to steal it. I had to wait for it to reset and make sure i unlocked it with the key. Also make sure if you have one of those keys with the chips in it that's it's near the steering wheel when you're turning it on. If you've lost that and it's required for your car it could cause the same problem. Once I got a new battery the problem went away. I actually ended up getting it towed to the shop because it wouldn't allow me to start it at all.

This is part of the advanced passive anti-theft. Your key has a unique code in it that has to be specially programmed by an auto shop so that people can't just make a copy. If you try to start the car and the engine doesn't detect the code from the key it will think that you are trying to "steal" your car with a fake key. It will then cut off the fuel pump so your car can't start. You will most likely have to take it to a dealer to have a new key made, or you can try to use another key if you have one. As for the honking and flashing lights, that's your car alarm going off because of the detected "fake" key.

This happened to me, but even worse! The interior light never went off unless I removed a fuse. But then the horn wouldn't honk. And also the seatbelt tone would beep constantly as long as my car was on. (drove me nuts!)

It must be the fuses.

clean check and tighten the rear lamp connecters it is a possibilitiy that your bulb failure warning unit is faulty as the brake lamp circuit runs through it. check out your stop light switch as well

This problem is most likely tied to your security system

you turn on the alarm its to stop theft