Depending on what is going on, might need to get down to the spiral clock spring to fully diagnose the switch.
Before you start, make sure the wheels are pointed straight ahead - note position of the steering wheel. If you need to get to the clock-spring, will likely need a puller - lots of different ones out there. You could make one yourself, if you have the raw materials. Otherwise, you can rent a steering wheel puller from an autoparts store fairly inexpensively.
Disconnect the negative battery cable, wait at least 5 minutes before you start poking at the airbag. You can also step on the break pedal - some people feel this helps, but I've always made sure to give it lots of time. Do it first thing before you do anything, then in the mean time, you can get all your tools/supplies together.
If you look on the sides of the steering wheel mounted airbags - there will be a torx screws on each side, I think they are size T-30, but I don't remember off the top of my head.
Airbag module will pop off at that point - the horn contact is underneath it (part of the assembly). Unfortunately, I don't remember if the contact can be separated from the airbag module - might all be one piece = $$$ to replace. Usually, the contact itself if fine, its a broken wire in the clock-spring that is the real culprit. To get to that - you'll have to pull the wheel off with the puller, don't forget to remove the two stalks on the side, if you haven't already done so.
You have to be very mindful NOT to check resistance or continuity check the airbag. Depending on your meter, it could jumpstart the airbag and you'll have a really bad day.