Jayco Greyhawk – AC Capacitor & Fan Motor Service

Jayco Greyhawk – AC Capacitor & Fan Motor Service

by

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

Parts & Tools You’ll Need

Step 1: Diagnose AC Performance Issues

Start by running your air conditioner for 10-15 minutes and use the non-contact infrared thermometer to measure the temperature of the air exiting the roof unit—it should read between 40-50°F for optimal cooling. If the AC runs but produces weak airflow, makes humming sounds without the fan spinning, or cycles on and off rapidly, you likely have a failing capacitor or motor. Document these symptoms and check your Jayco Greyhawk’s AC unit model (typically found on a label inside the shroud) to confirm whether you have a Dometic or Coleman-Mach system, as this determines your exact replacement parts.

Step 2: Power Down and Access the Unit

Turn off the AC at your interior control board and kill power at the breaker—do not skip this step, as capacitors retain electrical charge and pose shock hazards. Wait 5 minutes, then climb onto your Jayco’s roof with a flashlight and locate the rooftop AC shroud, which is typically a white plastic box measuring roughly 28 inches long by 15 inches wide. Unbolt the four corner fasteners (usually 3/8-inch bolts) securing the outer AC shroud cover and carefully lift it away, setting it on a clean surface to avoid losing small components or damaging the gasket.

Step 3: Remove and Inspect the Capacitor

Locate the dual run capacitor mounted on the side of the AC housing—it’s a cylindrical component approximately 3-4 inches tall with two wire terminals on top. Before disconnecting anything, take a photo of the wire positions, then use an insulated screwdriver to carefully discharge any residual electrical energy by briefly touching the screwdriver to both terminals simultaneously. Unbolt the capacitor bracket (typically one 1/4-inch bolt) and carefully slide the connector terminals off the old capacitor, then compare the microfarad (µF) rating printed on the old unit with your replacement RV AC dual run capacitor to ensure they match—common ratings are 35/5µF at 370V.

Step 4: Service and Clean AC Coils

While the shroud is off, inspect the evaporator and condenser coils for dirt, debris, and algae growth, which restrict airflow and reduce cooling efficiency. Apply the AC evaporator/condenser coil cleaner foam according to product instructions—typically you’ll spray it generously across the coil fins, let it sit for 10-15 minutes, then rinse thoroughly with a garden hose using moderate pressure to avoid bending fins. Use the fin comb / coil straightener tool to gently straighten any bent cooling fins by working the comb carefully across the coil surface; straightened fins improve heat transfer significantly.

Step 5: Replace the Fan Motor Assembly

Disconnect the fan motor electrical connector and unbolt the motor mounting bracket (typically three 1/4-inch bolts securing it to the AC housing frame). Slide the old RV rooftop AC fan motor straight out and position your replacement motor so the mounting holes align exactly with the housing—the motor shaft should point downward into the fan wheel. Reinstall the three mounting bolts snugly but do not overtighten, as this can crack the plastic housing; aim for hand-tight plus a quarter turn. Reconnect the electrical connector, ensuring the connection clicks fully into place and the wires show no signs of corrosion or damage.

Step 6: Install New Capacitor and Verify Connections

Insert the new RV AC dual run capacitor into the bracket and secure it with the mounting bolt, then use your reference photo to reconnect the wire terminals to the correct positions on the capacitor—reversing polarity will immediately damage the unit when powered on. Double-check that both terminal connections are tight and seated fully, with no exposed copper visible. Visually trace the thermostat / control board wires to confirm they remain undamaged and properly connected throughout the unit, as any loose connections will prevent proper AC operation or cause intermittent failures.

Step 7: Reseal Unit and Test Full System

Remove the old AC roof gasket and clean the gasket surface on both the shroud and housing with a dry cloth to remove debris. Install the new AC roof gasket and position the shroud cover back onto the unit, then reinstall the four corner bolts and tighten them in a cross pattern (top-left, bottom-right, top-right, bottom-left) to ensure even pressure; final torque should be snug but not over-tightened. Apply AC self-leveling sealant around the perimeter seam where the shroud meets the roof housing. After allowing 24 hours for sealant to cure, restore power at the breaker, set your interior thermostat to cool mode, run the AC for 30 minutes, and verify that airflow is strong and cold air exits vents at 40-50°F using your infrared thermometer—the system should cycle normally without humming or stuttering.