So I dug this post out from the past. I have had bad luck with dealers, so I generally avoid their service departments. So I finally took the Tacoma to a dealer for the stack of recalls (Springs, Frame) and asked them to check the air bag light. I dropped the truck off last night, so they had it in the shop first thing in the morning. By 9:00 am the service writer called me. Airbag light was diagnosed to the same front air bag sensor, along with the wiring harness. No big deal, they have the parts in stock (air bag sensor, wiring harness repair kit) + 3 hours of labor. for a charge of just under $800 - Done. After the initial estimate from $3K from the independent Toyota mechanic, it seem like a bargain. No air bag light = happy face.
P.S. - I don't need a new frame under the Tacoma. The service righter said some people are happy when they hear they don't need a new frame, and others are sad when they hear they don't need a frame. I guess I was happy - I can't imagine the truck being the same after replacing the fame.
Bottom line - I guess I should have received a second opinion soon. Also makes me question my independent Toyota mechanic some.