Performed fall maintenance on furnace. Tstat properly calls for heat. Air filter recently replaced. Performed safety inspection no gas leaks, checked electrical connections, heat exchanger shows wear and thermal stress points but no visible breaks. Pulled and cleaned ignition components, burners, orfices and flame sensor. Hot surface igniter ohms within spec at 79, taped wires which were chewed by rodents exposing high voltage. Blower motor fla 3.3A. Inducer draft motor fla .8/1.4fla. Secondary pan shows previous water damage. Replaced Single Run Capacitor for blower motor reading below tolerance.