Entegra Cornerstone – AC Capacitor & Fan Motor Service

Entegra Cornerstone – AC Capacitor & Fan Motor Service

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Complete repair guide for the Entegra Cornerstone – AC Capacitor & Fan Motor Service. Follow these steps to diagnose and fix the issue yourself.

Parts & Tools You’ll Need

Step 1: Diagnose AC Issues & Prepare Workspace

Start by running your Entegra’s air conditioner and listening for unusual humming, clicking, or grinding sounds that indicate capacitor or motor failure. Turn off power at the main breaker and disconnect the negative battery terminal to prevent electrical shock. Locate your rooftop AC unit (typically a Dometic or Coleman-Mach model) and gather all necessary tools, parts, and safety equipment including a non-contact infrared thermometer to verify cooling performance later.

Step 2: Remove Rooftop AC Shroud & Gasket

You’ll need to remove the rooftop AC shroud/outer cover by unbolting the 4-6 fasteners around its perimeter using a socket set. Carefully lift away the shroud and inspect the AC roof gasket for cracks, hardening, or deterioration—this is your opportunity to replace it if compromised. Set the shroud aside in a safe location and note the gasket’s position for proper reinstallation with the new AC roof gasket & self-leveling sealant.

Step 3: Disconnect & Test Capacitor Unit

Locate the RV AC dual run capacitor (typically a cylindrical component rated 35-50 microfarads) and use an insulated screwdriver to discharge any residual electrical charge by touching the terminals together. Disconnect the capacitor leads by unbolting or unclipping them from the motor terminals, photographing the wire configuration for reference. Use a multimeter set to capacitance mode to test the faulty capacitor—if readings show zero or significantly below the stated microfarad rating, replacement is confirmed.

Step 4: Replace Capacitor & Inspect Motor Leads

Install the new RV AC dual run capacitor by reconnecting the leads to the exact same terminals in the same configuration you documented. Ensure the capacitor sits securely in its mounting bracket and won’t vibrate loose during operation. While you have access, inspect all motor electrical leads for corrosion, burns, or loose connections—clean any oxidation with fine-grit sandpaper or electrical contact cleaner.

Step 5: Service AC Coils & Check Fan Motor

Apply AC evaporator/condenser coil cleaner foam to both the indoor evaporator coil (visible inside your unit) and outdoor condenser coil, allowing 10-15 minutes for the foam to break down dirt and debris. Use a fin comb/coil straightener tool to gently straighten any bent cooling fins, which improves airflow efficiency by up to 20%. If the fan motor is sluggish or won’t spin freely by hand, remove its mounting bolts and replace with the new RV rooftop AC fan motor, ensuring proper blade clearance.

Step 6: Reinstall Gasket, Shroud & Seal Seams

Position the new AC roof gasket around the mounting flange, then carefully lower the shroud back into place and hand-tighten all fasteners. Apply AC roof gasket & self-leveling sealant around the entire perimeter where the shroud meets the roof, using a caulk gun to create a continuous ¼-inch bead that will self-level over 24 hours. Torque all shroud fasteners to 15-20 foot-pounds in a cross-pattern to ensure even pressure and prevent leaks.

Step 7: Test System Performance & Verify Cooling

Restore power at the main breaker and battery terminal, then set your RV AC thermostat/control board to cool mode at 72°F to initiate startup. Run the unit for 15 minutes and use the non-contact infrared thermometer to measure condenser coil outlet temperature (should drop to 90-100°F) and cabin temperature reduction (typically 3-5°F every 5 minutes). Listen for smooth motor operation without rattling, confirm the fan runs at full speed, and check for any water leaks around the new gasket and sealant.