My fc is a 88 gtu
today I turned off my car and walked away.
suddenly it started horning and front and tail light keep flashing. I unplugged the battery to stop it.

any idea?

 

It's called a Car alarm.

 

but why it will happen?
is it a bad thing?

 

If its motion activated a passing train or semi can set it off. If its not then dunno if its new to you see if you can find an aftermarket security system if you have one it can be removed or maybe get a new remote for it.

 

Same thing jus happened to me. How do u jus disconnect it ?

 

Also how would u go about getting a new remote.

 

i just disconnected the battery. that turned off everything

 

The shock sensor on the aftermarket alarm might be faulty or the stock alarm might still be connected along with an aftermarket alarm

 

might be a good idea to just crawl under the dash and see if you can locate an after market alarm brain. If you find one and don't have a remote, remove it and reconnect the wires back to factory. Having an alarm that you can't control is useless, especially if it has an immobilize... I've seen that happen more than once when a car gets towed in with a no start.

 

my friend bought a car that was hacked to put a rb into. long story short there was an alarm on it, whenever he closes the doors the hazards flash. I dont know if this helps but if thats the issue maybe take it to a shop that installs systems. Have them look at it and possibly uninstall if that is your issue.

 

so,that is all good to stop the noise but what about the next time it happens?
You need to know if it is stock or aftermarket,then take it from there.
There is info on the stock alarm if you search for it.( I AM my own car alarm!)
Aftermarket is more tricky and you would have to either find a dealer or at least get the model and the installation manual and totally remove it.