odd beep

I was working on my Mother in laws 98 Ford Explorer Sport, and noticed that for about the first minute or so, that the engine is running, I get a electronic tone from inside the dash, it is about a 1 second "beep" and it will do this for about a minute and then stop. Could the alarm be going bad?

does the air bag light prove out when the key is turned on?

Actually, I don't think it does.

the air bag system has and audible tone to warn you when it has lost the ability to light the warning lamp - this may be as simple as a burnt out bulb wiring or even a module - - just look for the air bag light to come on when you start the car - if no light - start looking in that direction