A long, sharp peircing "beep" noise.?

Question

My mom has a 2002 Honda Civic LX Sedan, and when she takes out the key and when the door is open is makes a long, sharp peircing "BEEEEEEEP" noise. I thought it was the headlights on, because when the headlights are on it makes that noise when the door is open, but that wasn't the case. It makes a long beeeeep noise with the key out, headlights off, and door open, when the door is closed it stops. My dad is a mechanic but he's not home to do it himself, he just told me to spray WD40 inside the key hole and stick the key in and out and lubricate it because something might be stuck. Should I be doing that? Or what's wrong?

Answer 1

Sounds like a malfunction of the alarm warning of a door being ajar or open when the key is inserted and/or the car is moving.
WD40 will not do any harm. Just wipe away any drippings.