On the airbag light, your thought and the comments above on what caused it are exactly right. The standard sequence is:
- something in the door breaks
- disassemble the door, get to the airbag, disconnect the battery to be safe, disconnect and remove the airbag
- during the rest of the repair, find some reason you need to restore power (e.g., adjusting window). Restoring power while the airbag is disconnected sets the light.
Like you, my car came like this when I bought it. PO fumbling attempt at fixing the driver's window regulator. I had no luck resetting it with a standard code reader or a lot of time with the battery disconnected.
I then bought a single purpose tool on eBay that did nothing other than reset the light. Worked!
A couple of years later, I got a Foxwell, which resets the light with no problem.
I do also have the PA Soft, but did not try, since the Foxwell does it so well.
Considering how often something in the doors fails, having a tool to easily reset the light is very useful, I have found. It is nice not to need to worry about triggering the light while solving other problems. That's how I do it - safety and convenience first, figuring I can reset the light when all is done.
There is also a chance that they failed to plug the airbag back in, or even that they damaged the connector while fumbling with it or hammering it back into place.
