Arrived on site to diagnose a non operational 1989 furnace. Upon arrival spoke with client as he stated he just had a Ac and coil installed by us previously and now is having issues with furnace and blower motor. Had client show me system as he was also trying to fix it himself since he is familiar with system. Client showed me what he was having issues with and he thought the door switch was not operating properly. Upon arrival cycled system with the door switch and system cycled properly over 15 time on and off with client. Advised him of condition of furnace and blower motor is leaking heavily oil and is heavily hammered with dirt build up. Blower wheel is heavily covered in dirt build up accumulating from the past years and is creating high stress and wear on motor. Advised possibility of Main circuit board can be faulty as well due the age as it was replaced already once in past. Found that furnace is on its own breaker switch but the breakers had a bar which was connected on mult