5.0 help v. 5 beeps

I was taking the stereo out of the 5.0 and seeing what I could re-do the horrible alarm install. I see a blue box mounted up behind the dash, there was a plug not plugged in so I plug it in thinking Ive done right.
Or not now the dash beeps 5 times pauses and beeps 5 more.

What is the annoying as hell beeping? I assume something with the airbag? The is no airbag light or anything it just beeps and beeps and beeps ect… you get the point

put the bulb back in for the airbag … that will stop your beeps

that sounds fun to access… I didnt realize that the system was so anal back then.
Also the beeping will cut out and stop now and then no wires or anything just movments in the seat…