For this job, Technicians arrived to change out a transformer from a past service call. After installation of transformer the technician performed a full system evaluation to ensure proper operation for heating season. Technicians found the main breaker on the unit is arcing real bad, The indoor coil is starting to get pretty dirty, as well as The unit is starting to grow black substance all over the blower area and coil. Customer wants to move forward with the transformer and breaker. She wants us to come back Friday to perform the other repairs.