Air bag light - spiral coil assembly?

My airbag light comes on after a few seconds of driving, and my dealership says it is the spiral coil assembly that is at fault. Before I took the truck (2006 Tacoma) to the dealer I checked the wiring that I could find and unhooked the battery to restart the sensors, and this did not remedy the situation. One person at the dealership seemed a little surprised that the horn still works, given the diagnosis.

So, is there is something else I should check?

If the spiral coil needs replacement, is this something a handy non-professional could tackle? Any special tools required?

 

Thanks for the schematics, Ben. That's a great help.

Would you know if the "spiral coil assembly" that the dealership quoted (#8430604080) is the same as the "sub assembly" right under the steering wheel? If so, replacement doesn't look too bad.

 

I checked with the link you sent, again very helpful. At least it seems like the work is in the cab, and does not involve the whole steering column.

I am either cheap or naiive, or both, but I can't bring myself to spending $400 for this repair, so thanks for your help.

 

Just so you know thats a SRS component that has a warranty of 5 years or 60k miles (whichever expires first) from Toyota