Complete repair guide for the Keystone Arcadia – AC Capacitor & Fan Motor Service. Follow these steps to diagnose and fix the issue yourself.
Parts & Tools You’ll Need
- RV AC dual run capacitor (Dometic/Coleman-Mach)
- Rooftop AC fan motor
- RV AC thermostat / control board
- AC evaporator/condenser coil cleaner foam
- Rooftop AC shroud / outer cover
- AC roof gasket & self-leveling lap sealant
- Fin comb / coil straightener tool
- Non-contact infrared thermometer
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Step-by-Step Repair Guide
Step 1: Diagnose AC Issues and Safety
Start by identifying whether your AC is underperforming due to capacitor failure (weak cooling, humming sounds) or fan motor issues (no airflow, grinding noises). Before beginning any work, turn off power at your RV’s breaker panel and allow the system to cool for at least 30 minutes to safely discharge any residual electrical energy in the capacitor.
Step 2: Remove Rooftop AC Shroud Cover
Climb onto your Arcadia’s roof and locate the four corner bolts securing the AC shroud to the rooftop unit. Carefully unbolt and lift away the outer cover, setting it aside on a clean surface to prevent damage to the fins and internal components during your service.
Step 3: Replace Dual Run Capacitor
Disconnect the wire terminals from your old capacitor using needle-nose pliers, noting their positions or taking a photo for reference. Install the new Dometic/Coleman-Mach dual run capacitor by firmly pressing the terminals onto the corresponding posts, ensuring tight connections to prevent arcing and operational failures.
Step 4: Service Fan Motor Assembly
Unbolt the fan motor from its mounting bracket and carefully disconnect its electrical connector, then install your replacement motor in reverse order. Apply a small amount of dielectric grease to all electrical connections to protect against moisture and corrosion in the rooftop environment.
Step 5: Clean AC Coils Thoroughly
Spray the evaporator and condenser coils with AC coil cleaner foam, allowing it to sit for 10-15 minutes to dissolve dirt and debris buildup. Use your fin comb tool to gently straighten any bent fins, improving airflow efficiency and cooling performance across both coil sections.
Step 6: Reseal and Reinstall Shroud
Apply self-leveling lap sealant around the rooftop gasket perimeter and underneath the shroud edges to prevent water infiltration and air leaks. Carefully lower the shroud back into place and reinstall all four corner bolts in a cross-pattern, tightening gradually to ensure even pressure and proper sealing.
Step 7: Test System Performance Thoroughly
Restore power at your breaker panel and set your thermostat to cooling mode, listening for normal compressor startup and fan operation. Use a non-contact infrared thermometer to verify that cold air is flowing from vents (typically 15-20°F cooler than return air) and check that the rooftop unit runs smoothly for at least 15 minutes without unusual noises.
Recommended Parts
| Part | Link |
|---|---|
| RV AC dual run capacitor (Dometic/Coleman-Mach) | View on Amazon |
| Rooftop AC fan motor | View on Amazon |
| RV AC thermostat / control board | View on Amazon |
| AC evaporator/condenser coil cleaner foam | View on Amazon |
| Rooftop AC shroud / outer cover | View on Amazon |
| AC roof gasket & self-leveling lap sealant | View on Amazon |
| Fin comb / coil straightener tool | View on Amazon |
| Non-contact infrared thermometer | View on Amazon |