Beeping noise like my flashers are on it don't do it all the time on 2000 Lincoln Town Car

I bought this car a couple of days ago it runs great I have driven it about 75 miles now after I start the car a beeping noise continues like my seat belt isn't fastened I was told to remove the negative cable to reset computer I did now it is a faint nise like my flashers are on it did this for about a 12 mile drive and now no noise

Asked by for the 2000 Lincoln Town Car
Are there any signs of an aftermarket alarm/security system?
when i turn on my turn signals the flash but after the turn is complete you can still here the sound faintley of flashig also the beeping sounds like seat belt warning it goes off about five times then stops its the sound of the flashers with out using the signals that scares me
Probably best to bring to a shop and SHOW the tech. what it is doing. It may be something simple.
1 more answer
possibly warning buzzer for something...