Complete repair guide for the Keystone Sprinter – 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 blowing warm air, making unusual noises, or not running at all—these symptoms often indicate capacitor or fan motor failure. Before beginning any work, turn off the RV’s AC system completely, switch the breaker to OFF, and wait 5 minutes to allow residual power to discharge from the capacitor to prevent electrical shock.
Step 2: Remove Rooftop AC Shroud Cover
Climb onto your RV roof and locate the outer shroud covering your Dometic or Coleman-Mach AC unit, typically held by 4-6 Phillips head or hex bolts. Carefully remove these fasteners and lift away the shroud, setting it aside on a clean surface where you can safely work without dropping it.
Step 3: Disconnect Old Capacitor and Motor
Using a non-contact voltage tester, verify that all power has been discharged from the dual run capacitor before touching any electrical components. Photograph the wire connections for reference, then carefully disconnect the capacitor terminals and fan motor leads, noting their exact positions so you can reconnect identical wires to the new components.
Step 4: Clean Evaporator Coils Thoroughly
Apply AC evaporator coil cleaner foam to the visible cooling fins and coils, following the product instructions for dwell time and rinsing. Use your fin comb to gently straighten any bent fins, which improves airflow and cooling efficiency, then allow the coils to dry completely.
Step 5: Install New Capacitor and Motor
Position your new dual run capacitor in the same location as the original, ensuring it sits securely and won’t vibrate during operation. Connect the new fan motor and capacitor wires to their corresponding terminals using your photo reference, double-checking each connection is tight and properly seated.
Step 6: Reseal and Reinstall Shroud
Apply self-leveling lap sealant around the gasket area where the shroud contacts the roof to prevent water infiltration and air leaks. Carefully lower the shroud back into position and reinstall all bolts in a criss-cross pattern, tightening each bolt incrementally to ensure even pressure and a watertight seal.
Step 7: Test AC Performance and Output
Restore power to your AC system, switch the thermostat to cooling mode, and let the unit run for 10-15 minutes while checking for proper airflow and cooling. Use a non-contact infrared thermometer to measure the temperature of the supply air coming from your vents; it should be 15-20 degrees cooler than the return air, indicating the system is functioning correctly.
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 |