DIAGNOSIS The convection fan motor bearings are failing or fan blades are contacting the housing. Debris ingress or heat stress is the typical cause. The fan is located behind the controller assembly.
FIX Access and inspect the fan. Unplug the grill and let it cool. Remove the four screws securing the control panel assembly. Gently pull the assembly forward. Locate the black plastic fan housing. Inspect for visible obstructions like a stray pellet, wire, or carbon buildup on the fan blades. Remove any debris. Manually spin the fan to feel for grinding or catching.
IF THAT DIDN'T WORK The fan motor assembly likely requires replacement. It is not a serviceable bearing. The part is the combustion blower motor, Pit Boss part number PB2000003. Replacement involves disconnecting the wiring harness and removing mounting screws. Match wire colors during reconnection.
HEADS UP A failing fan will impact temperature stability and smoke quality. The grill relies on this fan for consistent combustion air flow. Do not operate the grill for long cooks with a malfunctioning fan, as it can lead to poor burns and temperature swings.