Troubleshooting a no heat call on a Heil heat pump system. Unit not coming on at all. Found blown 3 amp air handler fuse. Found low voltage short on high pressure inside heat pump. High pressure switch wires rubbed through onto metal to cause short, blowing the fuse. Fixed wiring, secured away other wires to prevent it from happening again, replaced fuse, and checked over heating operations, as well as heat pump defrost operations.