Your cruise control issue may not be an AP issue.
Work Horse bought the chassis (P32) IN NOV 1999 and continued to build for WH for "some" time.
First place to look is the RGS, "Rotten Green Switch", may be "under the hood" in your configuration. In all probability, you have the "J71" system with the majority of parts parts located there. The "green" switch may be brown in your case, same part different GM part #. Look on E-Bay.
Disconnect the electrical connector, examine and if you see hydraulic fluid there, replace the switch.
There is much info here and elsewhere. If your Vin# begins with a 5, then you are a WH chassis go to IRV2.com and click on appropriate discussion, WH/Chev.
As a resource source, check with Roger, aka Old Used Bear on the AP library, the resident expert on the J71 system . Provide pertinent details of your coach and failure mode.