Yeah.... Our 05' Yukon did the same thing yours was doing.
Bosses 05' LLY actually caught fire right in front of us in our shop parking lot. Luckily we smothered it out. Resistor shorted/overheated, plug end melted, melted coating off wires and hot wire fused together with rest of harness. It became a hot glowing ball which ignited dirt/debris/random little papers that had fallen from glove box area down into that hvac cover. Melted through the foam insulation on back of hvac cover and through the cover. Dripped hot molten plastic onto the carpet and floor mat. Crazy!