2008 Silverado 1500 extended cab 4x4. No power to right heated mirror and rear window defrosting equipment. Full continuity for both mirror and back window heat elements so the problem is somewhere in the wiring/connectors.
Left mirror heats fine. Is there a common junction for wiring to the right mirror and the rear window? That would seem the best place to start. Or a connector with both circuits running through.

I haven't yet found a wiring diagram that I can profitably use to trace these wires.

Thanks for any help.