I have a question regarding the alarm of my 2001 land rover disco II. Everytime i used to lock the doors using the key, it used to honk the horn for a second. But lately, its stopped doing that. The red light for the alarm still goes on, but it doesnt honk. What is the problem?

 

It should only honk if one of your doors/trunk/hood is open. So, likely one of your latches/sensors was not fully closed (likely the hood I suppose if no interiors lights were on), and now it is. Test out the alarm. Open a window, lock the doors and open a door and see if it is activated.