Passenger Airbag electrical issue

My airbag light came on in my 1st gen tacoma last week. I think this happened when I was working on my amp, got a short circuit, and threw a spark to my frame. I took my truck to my mechanic, and he told me that there is an electrical issue in my passenger airbag and I need a new airbag.

He suggested that I find a used airbag at a junk yard and ask then to cut the wiring harness, too. I asked him if this will be a big job to replace once I get him the parts, and he said he wouldn't know until he started. My questions are:

1) Has anyone had a passenger airbag die due to an electrical issue? Does this check out? Is there any obvious thing he may have overlooked?

2) Does anyone have any recommendations for sourcing a replacement airbag?

3) Is it a lot of work to get into the dash and replace an airbag?

THanks
Ryan

 

Anybody have any tips for replacing an airbag? Is this going to take a mechanic many hours to do?