Using the TC and AB pins on the diag port I reset the airbag light on my 1997 Lexus LX450. The trick seems to be a good connection between the ports and the ground.
What I did:
1. Connect wires to TC and AB ports.
2. Turned ignition on (unsure if it needs to be turned off/on again after every attempt, I did turn off and back on after each try).
3. Grounded TC, immediately alternated and grounded AB, and repeated
4. Grounded TC and held for 6ish seconds
More information available on ih8mud: forum.ih8mud.com/threads/fzj80-airbag-light.427318/