You can by-pass the horn pad on the steering wheel and install an after-market Horn Button to operate the horn, and you can purchase an after-market Horn Button from most auto part stores for under five dollars, and there are a few different designs that you can choose from.
You will also need enough ground wire to wire the horn button into your vehicle, and most likely a few wire connectors, and that can all be figured out once you actually see the Horn Button that you purchase.
To install the Horn Button:
First locate the turn signal switch wire connector and it should be on the lower right side of the steering column.
Then locate the Horn wire, it will have battery voltage at the wire and when the horn wire is grounded the Horn will operate or sound, and usually GM used a Black wire with an Orange stripe for the Horn wire at the vehicle wire connector for the turn signal switch from the vehicle wire harness, and the wire usually changed to a solid Black wire on the wire connector from the turn signal switch. However that is not always the case, and the wires should be tested to be certain of the Horn wire.
You can connect a test wire to a good ground and quickly make contact with the wire that you are testing and when the Horn sounds then you have found the right wire. (make contact for only a second and do not ground the wires that you are testing for more than a second or you could blow a fuse)
Once you have successfully located the Horn wire, then on the wire connector from the turn signal switch, cut the horn wire about three inches from the wire connector for the turn signal switch. (or at least enough to connect a wire to the cut Horn wire from the turn signal wire connector)
The rest is simple, you just connect one of the wires from the Horn Button to the cut wire from the turn signal wire connector, and then connect the other wire from the Horn Button to a good ground, and then test the operation of the Horn Button, and if the horn is working with the new Horn Button then mount the Horn Button where
you want it to be and the job is complete, and you should then have a fully functional horn again.
I have made you a wire diagram to help assist you, but it is only for a referencre and the wire colors might not match, so be sure that you actually test the wires to find the actual wire for the horn. Let me know if you require any further assisance.