Winnebago Minnie Winnie – AC Capacitor & Fan Motor Service

Winnebago Minnie Winnie – AC Capacitor & Fan Motor Service

by

Complete repair guide for the Winnebago Minnie Winnie – 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 and Prepare Workspace

Start by running your Minnie Winnie’s air conditioner and listen for unusual humming, buzzing, or complete failure to cool. Use the non-contact infrared thermometer to measure the temperature difference between the return air (should be room temperature) and the supply air (should be 15-20°F cooler); a difference of less than 10°F indicates a failing capacitor or fan motor. Turn off the AC at the thermostat, kill the main breaker, and wait 5 minutes to ensure all power is safely discharged from the capacitor before beginning work.

Step 2: Remove Rooftop AC Shroud and Gasket

Climb onto your RV roof with a Phillips screwdriver and locate the four to six fasteners securing the rooftop AC shroud/outer cover. Remove all fasteners and carefully lift the shroud straight up and away; note the position of any wiring harnesses connected to the thermostat or control board. Remove the old AC roof gasket by prying gently with a plastic scraper, then clean the mounting surface thoroughly with rubbing alcohol and allow it to dry completely.

Step 3: Test and Replace the Dual Run Capacitor

Locate the cylindrical capacitor mounted inside the AC unit, typically rated between 30-50 microfarads (µF) for Dometic or Coleman-Mach units on the Minnie Winnie. Before removal, use a multimeter set to capacitance mode to confirm the capacitor is failing (reading should be within 10% of the rated value; significantly lower readings indicate failure). Disconnect the two wire terminals from the capacitor using a 1/4-inch socket, remove the mounting bracket bolt, and install the new RV AC dual run capacitor in reverse order, ensuring terminals are firmly seated.

Step 4: Inspect and Replace Fan Motor Assembly

Remove the fan blade by unthreading the center bolt (typically 3/8-inch) and sliding the blade off the motor shaft, then unbolt the motor housing from its mounting brackets. Spin the motor shaft by hand—it should rotate smoothly; any grinding, squeaking, or resistance indicates bearing failure and the need for replacement. Install the new RV rooftop AC fan motor by reversing the removal steps, ensuring the motor is fully seated in its brackets and the center bolt is torqued to approximately 12-15 foot-pounds; reinstall the fan blade with the curved side facing the intake direction.

Step 5: Clean Evaporator and Condenser Coils

Spray the AC evaporator/condenser coil cleaner foam directly onto both the evaporator coil (located inside the shroud) and condenser coil (the external side), allowing the foam to sit for 10-15 minutes to break down dust and debris buildup. Use a soft brush or the fin comb/coil straightener tool to gently straighten any bent fins and remove loosened debris; bent fins restrict airflow and reduce cooling efficiency by up to 25%. Rinse the coils thoroughly with a spray bottle of distilled water, working from top to bottom to avoid trapping moisture, then allow everything to air dry for at least 15 minutes.

Step 6: Reinstall Shroud with New Gasket Seal

Position the new AC roof gasket around the mounting flange of the AC unit, pressing it firmly into place to create an even, complete seal. Apply a continuous bead of RV AC self-leveling sealant around the gasket perimeter, then carefully lower the rooftop AC shroud/outer cover back into position, aligning all mounting holes. Insert and tighten all fasteners in a crisscross pattern (like tightening wheel lugs) to 15-20 inch-pounds to ensure even pressure and prevent gasket squeeze-out or air leaks.

Step 7: Test System and Verify Cooling Performance

Restore power at the main breaker, set your RV thermostat to cool mode at 72°F, and run the AC for at least 15 minutes to allow the system to stabilize. Measure the supply air temperature with the infrared thermometer—you should achieve a 15-20°F temperature drop and hear the fan motor running smoothly with no grinding or vibration. Check that the new gasket and sealant have created a watertight seal by visually inspecting the shroud perimeter and monitoring the interior ceiling area during the next light rain; any dripping indicates an incomplete seal that requires additional sealant application.