560sl. The shop had my steering wheel off to do some work and I'm wondering if the airbag connection is good if I don't get an indicator lamp. How do I know it still works?

Also, the horn doesn't work. The fuse is good and other items on that circuit work. The shop actually had the steering wheel off twice, and after the first time the horn worked fine, but not the second. They took it off again to fix something in the instrument panel. Is this just a connector that they might have forgetten to put back? How hard is it to remove the steering wheel? I'm gonna take it back to the shop, I just want to know how it works and what the likely scenario was.

Thanks, David.