Radio, Airbag, Seatbelt, Horn, are they all together?

[RDM3]

Ok this is odd, I have been having problems with the radio, seatbelt and airbag, lately I have started the X up and the radio would not come one, so I turn it off, start up and its fine, then there have been times where the airbag and seatbelt light are on, seatbelt is hooked and the radio won't come on, and airbag light won't go off, then again turn it off, start up and it is fine. Then the seatbelt light is off (hooked), airbag light is on, radio is not working and horn won't work.

So my question is, are the airbags, seatbelts, horn and radio all connected somehow?