One system tune up in Atlanta. Arrived on site, found package unit on right side of house. Customer complaint of bedroom not heating up, found it is due to improperly run Y. Found many spots in ductwork where rodent had chewed through ductwork. Found weak capacitor for blower motor, as well as duel run capacitor. Blower assembly is dirty and should be pulled and cleane, cannot access evaporator coil due to design of unit. Upon finishing tasks, I plugged disconnect in and unit started operating, but burner started rolling out and started to catch inducer motor wiring on fire. Unit needs to be replaced due to age and condition of system. Unit is not operational at this time. Left disconnect off because of heavy rollout.