Secondary Air Pump Won't Stop Running

[GeneP]

Bout 1/2 a year ago I got the P0410 code for a secondary air pump problem. I bought a new pump & hose but never got around to installing it, but the code disappeared and never came back since. Anyhow, today I just returned from a 500 mile all highway trip. When I pulled in the driveway & shut off the engine I heard what sounded like an electric motor continue to run under the hood. Sounds like its coming from near where the pump would be. Actually like a sick horn from the checkvalve next to the right side exhaust manifold. I pulled all fuses on the side of the dash & in the box under the hood and it still continued???? Finally I just pulled the battery cable till I can look further to avoid killing the battery. Truck is actually a 2000 Sonoma 4.3.
Any Suggestions???

Thanks,
Gene