Haynes manual has circuit diagrams and passenger fusebox layout but I'm afraid neither have airbag circuit details, just a warning:
"...This vehicle is fitted with a supplemental restraint system (SRS) consisting of a combination of driver (and passenger) airbag(s), side impact protection airbags and seatbelt pre-tensioners. The use of electrical test equipment on any SRS wiring systems may cause the seatbelt pre-tensioners to abruptly retract and airbags to explosively deploy, reslting in potentially severe personal injury. Extreme care should be taken to correctly identify any circuits to be tested to avoid choosing any of the SRS wiring in error... Note: The SRS wiring harness can normally be identified by yellow and/or orange harness or harness connectors."
I removed and replaced the front passenger airbag keyswitch from the glovebox without any problems when I was fitting a Dension unit to the CD player, but any other work on the airbag circuits I think I would leave to a dealer.