Your Coleman Mach AC unit on the 2019 Rockwood Minilite 2509s has developed a short circuit that's drawing power even when the AC is off. The fact that the fuse blows before it's even fully seated indicates a direct short to ground in the AC circuit.
You likely have an incompatible control box model. The 9430A751 with dual SIG terminals is designed for true multi-zone systems, while your single-zone setup needs a simpler control box with one SIG terminal.
When your RV A/C won't start after a capacitor change, check for blown fuses, thermal switch reset, proper wiring connections, and overheated compressor lockout. The compressor may need time to cool down before restarting.
Coleman Mach heat strips can be added using the Heat-Ready Control Box. This adds electric heat through your AC while keeping furnace independent. Verify AC model compatibility and check electrical capacity - heat strips draw significant amps.
Blinking LED on zone AC control board indicates fault. Zone 2 steady green means its working. Try swapping boards to confirm zone 1 board failure, then replace if confirmed.
Coleman Mach motor replacement with different shaft length needs wheel position adjustment, shaft coupler, or careful shaft trimming. Use puller to remove stuck blower wheel, never pry.
Coleman Mach AC uses gravity drainage through base weep holes - no pump or tubing. Dripping likely from closed vents disrupting airflow, gasket seal deterioration, or blocked drain path. Try running with vents open first.
Keep your RV comfortable in any weather with this AC, furnace, and heat pump troubleshooting guide.
Three year AC failure is premature - should be warranty covered. Normal lifespan is 10-15 years. Contact manufacturer (Dometic or Coleman) and dealer for warranty repair. Document failure before contacting for claim.
Micro-Air 355 wiring differs from RV Comfort.ZC for multi-zone operation. Zone issues likely from SIG1 and SIG2 wire configuration. Unused Yellow and Orange may be zone 2 controls. Contact Micro-Air technical support for specific wiring guidance.
When your RV air conditioner hums loudly but produces no airflow, it's typically caused by a seized fan motor, blocked vents, or debris in the fan assembly after sitting unused. Start by checking for obstructions and cleaning the unit thoroughly.