My understanding is that Keystone does not have wiring diagrams because the wiring depends upon the juice carpenter working that day and what mood he/she is in.
In ours, 3791RD, the fireplace quit working when a tech ran a screw through the wire in the outside wall trying to fix the loose half wall behind our recliners. They almost sent it back to Elkhart for that. I'd start looking around the living area to see if any other outlets are not working. We had an outlet behind the recliners that went out when the screw shorted the circuit.
Robert & Diana McNeal
2019 Montana Legacy 3791RD 20th Anniversary Edition
2014 F350 4x4 6.7L SRW