2002 Chevy Silverado auto seats and horn stopped workin

Hello, there should be a horn relay in the power distribution center under the hood. You can unplug the relay, use a testlite, two terminals should be hot? You can use a fused jumper on the switch/ load side of relay, the horn should honk. If it does, the problem may be on the control side of relay, ground. I can't rule out the relay at this point, the fuse for that circuit shows 15 amp.

I saw a 25 amp circuit breaker for the power seats. If that breaker is hot, maybe something wrong with the seat motor or something is causing a load on the motor?