Be sure to disconnect the battery first. The passenger airbag is held in place by a single, long, bolt that is screwed in vertically. If you place your head in the passenger footwell and look upward, you'll see a hole in the under dash "kneepad." Several inches up that hole is the airbag retaining bolt. You'll need a 10 mm socket on a six inch extension. Once that long screw is out you'll need to wiggle out the facia panel which is integral with the airbag assembly. On my 1993 W124, the two wires that attach to the back of the airbag/facia assembly were slightly different in color and tracer, so keep track of your wire polarity. It is a bit of trouble just to get to that one little screw that retains the center vent. Incidentally, the vent's fins are a bit frail so don't pull too hard on them. I fished a piece of clothes line into the vent, behind several fins and then back out again and used it as a "handle" to GENTLY pull as I released the clips on the left side of the vent. Good luck.