Buick/Olds: Buick horn repair, turn signal switch, buick skylark

Question
1991 Buick Skylark 4-cylinder sedan & horn repair:  Horn doesn't work on vehicle; wiring seems intact; has horn on driver and passenger side of vehicle--would both units need to be replaced?  Or if just one, which unit?  Any tips regarding how to determine what is most likely causing problem, from easiest to hardest?

Answer
It could need both horns but if one of them is shorted, the other one will not work. First unplug one of them and see if the horn blows. If not, plug that one back in and try the other.
If neither of them work, check for power to the horn using a test light connected to ground. Probe the wire with the test light while trying to blow the horn. If it lights, replace the horns. If it does not light you have a problem with either the horn relay, horn pad, or the turn signal switch, or wiring.