Complete repair guide for the DRV Mobile Suites – 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 Prepare
Start by identifying symptoms such as weak cooling, unusual noises, or complete AC failure to determine if you’re dealing with a capacitor or motor problem. Turn off your RV’s main electrical breaker and disconnect the battery to ensure your safety before working on any electrical components, then allow the roof-mounted unit to cool for at least 30 minutes.
Step 2: Remove Rooftop AC Shroud Cover
Use a socket wrench set to carefully unbolt the AC unit’s outer shroud, typically held by 6-8 fasteners around the perimeter. Document the bolt locations with photos and gently lift the shroud away, noting any gasket material for replacement during reassembly.
Step 3: Test and Replace Dual Run Capacitor
Use a multimeter set to capacitance mode to test the existing dual run capacitor, comparing readings to the manufacturer’s specifications printed on the unit’s label. If readings are low or nonexistent, disconnect the old capacitor’s wire terminals carefully and install the new one, ensuring terminals are firmly seated and matching the microfarad (µF) rating exactly.
Step 4: Inspect and Service Fan Motor
Spin the fan blade by hand to check for resistance or grinding sounds that indicate bearing failure requiring motor replacement. Clean the motor housing and fan blades with a soft brush, then apply a small amount of electric motor oil to lubrication ports if accessible.
Step 5: Clean Evaporator and Condenser Coils
Spray the AC coil cleaner foam directly onto the evaporator coils (inside facing) and condenser coils (outside facing), allowing it to sit for the time specified on the product instructions. Use a fin comb tool to carefully straighten any bent aluminum fins, working gently to avoid puncturing the delicate cooling lines running through them.
Step 6: Reinstall Shroud and Seal Roof
Position the shroud back over the AC unit and reinstall all fasteners in a crosshatch pattern, tightening evenly to avoid warping the cover. Apply self-leveling lap sealant around the perimeter where the shroud meets the roof, ensuring complete coverage to prevent water intrusion.
Step 7: Test System Cooling Performance
Restore power by reconnecting the battery and turning on the main electrical breaker, then set the thermostat to cooling mode and allow the system to run for 10-15 minutes. Use your non-contact infrared thermometer to measure discharge air temperature from the vent—properly functioning units should deliver air between 35-45°F when the outside temperature is 80°F or higher.
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 |