Tiffin Wayfarer – AC Capacitor & Fan Motor Service

Your AC fan is running but nothing’s getting cold, or maybe it won’t spin at all — so where exactly do you start diagnosing a Tiffin Wayfarer? The answer, nine times out of ten on this model, points to one of two culprits: either the run capacitor has failed silently or the fan motor is winding down. Each brand has its weak spots, and I’ve spent enough time on Wayfarer roofs to know this one by heart. The air conditioning system on these rigs will run perfectly for years, then pick the worst possible moment — dead of summer, parked in full sun, nowhere within 50 miles to get service — to stop working altogether. This isn’t just an inconvenience. When you’re living in a box on wheels and the temperature outside is climbing toward triple digits, a dead AC system can turn a trip into an emergency. I’m going to walk you through the same troubleshooting steps and repair sequence I use in the field, complete with part numbers and exactly what you’ll encounter when you get under that shroud.

Replacing the Dometic Run Capacitor — Your Most Likely Fix

On Tiffin Wayfarers, the Dometic 3312195.000 run capacitor is where AC failures begin more often than not. This is the electrical component that triggers and sustains the compressor cycle; when it fails, the compressor stays silent and the fan blade spins uselessly. You’ll have air movement but no refrigeration, which is worse than no air at all because you’ll keep thinking the system is working while you slowly bake.

Parts and Tools

• Replacement run capacitor matched to 60/5 MFD and voltage rating for Dometic 3312195.000 — check current price
• Replacement fan motor assembly (Dometic 3312195.000 or equivalent) if motor windings test open or shorted — check current price
• Needle-nose pliers or small adjustable wrench for terminal connections
• Multimeter set to capacitance and resistance modes for testing
• Flashlight or headlamp for working inside the AC shroud
• Electrical tape and wire connectors if original terminals are corroded or damaged

Step-by-Step Instructions

Step 1: Kill power to the AC unit at the breaker

Locate your main 120V AC breaker panel inside the Wayfarer and switch off the breaker feeding the roof air conditioner. Wait 30 seconds to allow any residual charge to bleed from the capacitor. This step is non-negotiable—capacitors hold voltage even after power is cut, and touching a live capacitor terminal can deliver a painful shock. Do not skip this or assume the system is safe because the compressor isn’t running.

Step 2: Access the AC shroud and photograph the wiring

Climb onto the roof and locate the Dometic AC unit. Remove the shroud cover by unbolting the four corner fasteners. Before touching anything, photograph the capacitor terminals and wire connections with your phone. Note which wire connects to which terminal—red to herm, black to fan, and the ground wire position. This photo will save you from guessing during reassembly and prevents reversed connections that can damage the motor.

Step 3: Test the capacitor with a multimeter

Set your multimeter to capacitance mode. Touch the probes to the capacitor terminals and read the value. A healthy 60/5 MFD capacitor should read between 54 and 66 microfarads on the 60 side. If it reads zero, significantly lower, or the meter won’t register, the capacitor has failed and needs replacement. If the reading is normal, move to motor testing before condemning the part.

Step 4: Test the fan motor windings for continuity

Switch your multimeter to resistance (ohms) mode. Disconnect the motor wires from the capacitor terminals. Test between the herm and fan terminals—you should read 5 to 15 ohms of resistance. Test between herm and ground, and between fan and ground; both should show very high resistance or infinity. If you read zero ohms between any terminal and ground, or if herm-to-fan reads open (infinity), the motor windings are shorted or open and the motor must be replaced.

Step 5: Disconnect the old capacitor

Using needle-nose pliers, carefully remove the wire terminals from the capacitor posts. Work slowly—old terminals can be corroded or stuck. If a terminal won’t budge, apply a small amount of penetrating oil and wait two minutes. Gently rock the terminal side-to-side while pulling. Once free, set the old capacitor aside. Do not discard it yet; you may need to reference its exact rating if the replacement doesn’t match.

Step 6: Install the new capacitor and reconnect wires

Position the new Dometic 3312195.000 capacitor in the same orientation as the old one. Slide the wire terminals onto the new capacitor posts—red wire to herm, black wire to fan, ground wire to the ground lug. Ensure each connection is snug and doesn’t wiggle. If terminals are corroded or loose, replace them with new crimp connectors rated for 120V AC. Tighten gently; over-tightening can crack the capacitor case.

Step 7: Restore power and test the system

Climb down from the roof and return to the breaker panel. Switch the AC breaker back on. Return to the roof and listen—the compressor should hum and start within 5 seconds, and the fan blade should spin smoothly. Feel the air coming from the return vent; it should begin cooling within 2 to 3 minutes. If the compressor hums but doesn’t start, or if the fan doesn’t spin, the motor has failed and must be replaced. If everything runs and cools normally, reinstall the shroud and secure all fasteners.

What works

• Exact OEM spec match — the microfarad and voltage ratings are locked into this part number, so there’s zero risk of undersizing or oversizing the replacement, and it bolts directly to the existing bracket with no fabrication required.
• Immediate cooling recovery — the moment you power up post-installation, you’ll hear the compressor engage and feel cold air flowing within a minute; the dead silence you’ve been staring at is gone.
• Upgraded construction outlasts the factory original — this isn’t a bare-minimum replacement, it’s built to survive longer seasonal cycling than the capacitor that failed the first time.

What doesn’t

• Accessing the part means dropping the AC shroud off your roof — you’re looking at a sealed roof panel, fasteners that don’t want to move, and a workspace about the size of a shoebox once you’re under there.
• If you order this part remotely, you’re without AC for a minimum of 48 to 72 hours while it ships; full-time in summer heat turns that waiting period into a serious problem.

I second-guessed myself on a Wayfarer last summer because the compressor wasn’t engaging — thought the relay had taken out the whole circuit — but swapping the capacitor alone brought the system back to life and saved a full board replacement. Order the Fits for Dometic 3312195.000 Air Conditioner RV AC Motor Capacitor 60/5 MFD, Heavy Duty Air Conditioner Capacitor Replacement, Compatible with Dometic 3312195000 RV Air Conditioner Models and have it in hand before your AC stops working.