Heater element and all thermostats checked out OK for continuity. Diagnosed the issue to be an internal fault within the motor switch. Unfortunately, for my model, the switch is integrated with the motor assembly. Also motor was a newer version that required a jumper that paired with the original wiring harness. Supplied instructions were good (with pictures).
Installation was straight forward but quite a bit of disassembly was required. Make sure you keep track of the screws and where they belong. Otherwise, I was able to complete the job with a Phillips screwdriver and 1/4" nut driver. Everything runs great now!