Thor Four Winds – AC Capacitor & Fan Motor Service

I’m standing in front of a Thor Four Winds right now with the access panel off the rooftop AC unit, compressor humming like it’s working hard but the fan blades aren’t moving at all. Hand on the housing—it’s hot enough that I’m not leaving my palm there long. This is the moment where most owners start pricing out a full replacement unit and calling their bank, but I’ve seen this exact scenario play out a hundred times, and it almost always comes down to two cheap parts: a failed run capacitor or a motor that’s seized up. Catch it early and you’re out maybe forty bucks in materials. Let it sit and cook the compressor? You’re looking at a four-figure hit. I’ve built a repeatable diagnostic process through countless flips and side-work troubleshoots—what you’re about to read is that actual sequence, field-tested on rigs exactly like yours, not some dealer pamphlet version. Before you start looking at replacement costs for the whole AC unit, walk through this first.

The Run Capacitor That Powers the Dometic Rooftop Fan on Four Winds Models

When your Dometic compressor is running—you can hear it laboring—but the fan motor stays locked and there’s no cold air moving through the ducts, a dead or failing capacitor is almost certainly your culprit. The capacitor is what shifts the electrical phase so the fan motor can turn; without it working, the compressor runs in a bind and slowly cooks itself toward failure.

Why this part works

• Matches the Dometic OEM part number 3312195.000 down to the terminal configuration—no splicing, no adapter hunting, it seats exactly where the old one came out.
• Rated at 60/5 MFD, which is the spec sheet requirement for Four Winds Dometic systems; slip it in, power up the AC, and the fan blade starts spinning instead of sitting dead.
• Built with thicker housing and stronger internals—not a disposable part that fails every season if you’re using your AC hard, it’s made to last if you’re not hammering it 24/7 in 135-degree conditions.

Where it falls short

• Standard shipping is 5–7 business days; if you’re stranded in August heat and need this installed tomorrow, you’re either expediting the cost or sitting tight, and neither option feels good when the temperature inside is climbing.
• Sometimes the capacitor is the messenger, not the disease—if that compressor was already pulling high amps before the cap failed, the motor windings inside may be heat-damaged beyond saving, and swapping the capacitor won’t fix a cooked motor.

I once swapped the capacitor on a Four Winds and the fan still wouldn’t turn, which made me wonder for a solid 20 seconds if I’d grabbed the wrong part—until I realized the motor shaft was seized from months of sitting idle. 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

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