Found unit not calling for cooling upon arrival. Made call for cooling and found indoor system cycled on outdoor system failed to cycle. Found disconnect fuse shorted not allowing proper voltage. Replaced fused. System cycled on without issue ran with 16 degree temp drop. Found systems furnace has rust holes in flue. Also found all 3 ac systems dirty covered with debris. Also found far system to back of building fan making access noise. Informed customer of possible issues in future. Informed customer of findings and offered service plan. Customer denied only wants HB3A performed today. No further concerns.