1 system ac pm check complete. Also did heating maintanence since customer missed it. Changed dirty filter. Found drain pan filled with water causing rust on drain pan. Drain line was clogged, blew water out but it has gunk all in it. Recommend condensate pump for system. Checked mechanical and electrical components, all in good shape. Chemically washed condenser coil and applied rust proof waxing. System operating at this time.