Dometic FreshJet 5 Start Capacitor Kit 4450037546

When your Dometic FreshJet 5 rooftop air conditioner hums but won't kick on, or the fan spins while the compressor sits dead, the start capacitor is the first thing to check. This is the genuine OEM Dometic replacement start capacitor kit for the FreshJet 5 Low Profile air conditioner series, part number 4450037546, and it ships with a fresh mounting strap so you can button everything back up the way it left the factory.

A start capacitor does one job, and it does it every single time the compressor cycles. It stores a jolt of electrical energy and dumps it into the compressor motor to give it the torque it needs to break away and spin up. Over years of hot afternoons and hard starts, that little can wears out. When it fails, you get the classic symptoms: a low hum from the unit, a breaker that trips, warm air instead of cold, or a compressor that tries and gives up. Swapping in a fresh capacitor is often the difference between a dead A/C and cold air by lunchtime.

Because this is the genuine Dometic part built for the FreshJet 5 Low Profile series, you don't have to guess at the fit. It's a direct OEM replacement, so the terminal layout and the capacitance match what the unit shipped with. That matters. Get the rating wrong on a generic can off the shelf and you'll be right back on the roof, or worse, chasing a compressor that won't start at all. This kit takes the guesswork out.

The included mounting strap is a small thing that makes a real difference. On a low-profile rooftop unit everything is packed in tight, and the A/C takes a lot of road vibration on travel days. A loose capacitor rattling around inside the shroud will chafe its wiring and shorten its life. The strap holds it firm against the chassis the way the original did, so the new part lasts.

Who's this for? Any RV owner running a FreshJet 5 Low Profile unit who wants to keep it going. If you're handy with a screwdriver and a set of spade connectors, this is a job you can knock out yourself in an afternoon. Owners consistently call the capacitor swap one of the easier rooftop A/C repairs. You pull the outer shroud, find the electrical box, and the capacitor is sitting right there. The hardest part is usually getting up on the roof safely.

A word of caution before you dig in. A capacitor can hold a charge even with the power off, so always disconnect shore power and the battery, then discharge the old capacitor across a resistor or an insulated screwdriver before you touch the terminals. Note which wire goes where before you pull anything, snap a photo with your phone, and transfer the connections one at a time to the new can. Take your time and it's a straightforward fix.

Not sure the capacitor is really the culprit? Here's the quick triage. If the fan runs fine but the compressor won't engage, the start capacitor is the prime suspect. If the whole unit is dead, check your breaker and the thermostat first. And if the capacitor looks swollen, bulged at the top, or is leaking, that's a dead giveaway that it's cooked and needs to come out. A healthy capacitor holds its shape and reads within spec on a multimeter set to the capacitance range.

This is a genuine Dometic component, not a shelf-stock substitute, so you get the exact spec the FreshJet 5 was engineered around and the peace of mind that comes with it. If your rooftop A/C has been slow to start, tripping breakers, or blowing warm on a hot day, a fresh start capacitor is the cheapest, fastest thing to try first. Keep a spare in the rig too. They're small, they're inexpensive, and there's never a good day for the air conditioning to quit.