New Horizons – RV Water Heater Thermostat and Heating Element Replacement

RV Water Heater Thermostat and Heating Element Replacement

“Drew, my New Horizons water heater won’t heat past lukewarm, and the dealer quoted me $850 just to look at it. I pulled the access panel and it looks pretty straightforward—can I swap out the thermostat and element myself?” That’s the text I got last month from a guy camped somewhere near Sedona, and it’s the exact setup I want to walk you through today. Here’s the thing, though: before you order parts and tear into your water heater, you need to know what’s actually broken. I’ve seen owners replace a heating element when the real culprit was a tripped high-limit reset button, or swap a thermostat when a loose wire connector was the whole problem. Test first. Then tear into it. But once you’ve confirmed the thermostat or heating element is genuinely shot, you want to do this replacement cleanly the first time—no leaks, no electrical gremlins, no cold showers at the next campsite. That’s what this guide covers.

Parts Needed:

• Suburban 232306 Thermostat Switch, Model: 232306, Outdoor&Repair Store (Part Number: 232306) ($18.99)
• Upgraded 520900 RV Water Heater Element For Suburban RV SW Series Electric Wa… (Part Number: 520900) ($17.00)
• Lrichy 110V/120V RV Water Heater Screw-In Electric Heating Element 110V/1400W… (Part Number: Replaces Suburban 520789/520900 • Atwood/Dometic 92249) ($21.97)
• VOTMELL 4 Rolls 1/2 Inch(W) X 520 Inches(L) Teflon Plumbers Tape,Pipe Sealing… ($3.59 ($0.90 / count))
• Nextronics Tool-Free Wire Connectors 25 Pieces – Quick Splice Terminal Blocks… ($8.99 ($0.36 / count))
• Suburban 232767 Water Heater Anode Rod (Part Number: 232767) ($25.99)

After years on the road, I’ve learned that a failed thermostat is almost always the first culprit when your Suburban water heater stops doing its job — and using the correct OEM part matters more than most folks realize. The Suburban 232306 Thermostat Switch is a direct-fit replacement that snaps into position without any guesswork. No adapters, no splicing, no hoping it’ll work — it just does. One installation tip: let the tank cool completely before you touch anything, and double-check that the reset button clicks firmly when you seat the new thermostat.

I keep a spare heating element tucked in my wet bay storage, and for Suburban SW-series units, this is the one I reach for first. The Upgraded 520900 RV Water Heater Element for Suburban SW Series is engineered specifically for these tanks, which means the wattage rating, thread pitch, and flange dimensions are all correct out of the box. The “upgraded” designation typically refers to improved corrosion resistance on the element sheath — something you absolutely want when that element is sitting in water full-time. Wrap the threads with fresh Teflon tape and torque it snug, not gorilla-tight, and it’ll seal cleanly every time.

If you’re running a 110V/120V system and need a budget-friendly backup option that doesn’t cut corners on safety ratings, this one has earned a spot on my shortlist. The Lrichy 110V/120V 1400W Screw-In RV Water Heater Element is a solid universal-fit choice when you’re in a pinch at a campground and the OEM part isn’t available locally. At 1400 watts, it delivers reliable recovery times without overtaxing your shore power connection. Just confirm your tank’s thread size before ordering, and always verify the element is fully submerged before energizing — running it dry even briefly will burn it out fast.

Step 1: Testing and Removing Failed Components

Begin by checking whether the heating element has actually failed. Kill the power first and drain the water heater completely. Once it’s empty and de-energized, disconnect one wire from the heating element’s power terminal. Pull out your digital multimeter and set it to ohms (resistance mode). Touch one probe to each terminal on the heating element itself. A healthy heating element reads somewhere between 8 and 15 ohms—most land right around 10 to 12 ohms on standard RV units. If your meter shows “OL” (open line) or infinity, the element is dead and needs to go. Anything far outside that 8–15 ohm window also means replacement time.

Once you’ve confirmed the heating element is bad, unscrew it from the tank. Grab your wrench—usually 1-1/8″ or 1-1/16″ depending on your model—and turn counterclockwise slowly. A bit of water may dribble out as you crack it loose, which is totally normal even after you’ve drained the tank. Pull the element straight out, and you’ll see the rubber gasket attached to it. Look over that gasket for cracks, deterioration, or places where it’s been permanently squished. Hold onto the old one as a size reference, even if you’re tossing the element. Run your eyes over the element itself too—scale buildup, rust spots, or a visibly cracked coil all point to failure and confirm your replacement was the right call.

Next, test the thermostat switch. You’ll find two thermostat switches mounted near the top of your water heater assembly. One controls the 12V propane side (you’ll notice a wider flat conductor), and one runs the 120V electric side (thinner wire). For electric heating troubleshooting, focus on the 120V thermostat. Pop off the rubber protective cap that’s covering the reset button. Scan the wire connections for any heat damage—discolored insulation, melted plastic, charred terminals, anything that looks cooked or corroded. Disconnect the two power wires from the thermostat’s bottom terminals. Switch your multimeter to continuity or low-ohms mode.

Touch your meter probes to both thermostat terminals. It should beep or read nearly zero ohms when the unit is at rest temperature—that means the switch contacts are closed. No continuity reading, or visible burn marks on the wiring, means the thermostat is toast and needs replacing.

Step 2: Installing New Components and Testing

Put your new heating element in place using the right sealing method. Start by scrubbing out the threaded opening on the tank—get rid of any leftover gasket material, mineral scale, and corrosion with a clean rag and a bit of mild soap if you need it. Take your new heating element and its gasket (or grab a fresh gasket separately if it didn’t come with one). Slide that gasket onto the element’s threads and nestle it up against the flange. Spin the element into the opening by hand first, turning clockwise. Go as far as your fingers will let you, then pick up the wrench. Tighten another 1/4 to 1/2 turn max—don’t gorilla-grip it, because that’ll trash the gasket seal or even crack the porcelain inside the tank.

The element should sit snug with the gasket making a complete, watertight seal. Connect the wiring to your fresh heating element the right way. Look for the two terminal posts on the new element. The hot wire (usually black or red) hooks to one terminal, and the ground wire (white or green) hooks to the other. Most elements don’t care which wire goes where—they’re non-polarized. Still, wire it the same way the old one was wired to keep everything consistent. Use wire nuts or crimp connectors rated for outdoor, damp environments. Cinch all connections down tight. Wrap each one in electrical tape as a moisture barrier. Make sure no bare wire is hanging around where it could touch the metal housing and short the whole thing out.

If you’re swapping the thermostat too, handle it with care and get the wiring back the way it was. Disconnect every wire from the old thermostat and pull out its mounting screws (usually two). Position the new thermostat in the exact same spot and angle as the original—it has to sit flush against the mount so it can sense temperature correctly. Screw it down tight and even flush. Reconnect your wires to the new thermostat’s terminals exactly as they were on the old unit. If you’re unsure, snap a photo of the old setup before you disconnect it. The hot wire goes to one terminal, and the wire heading to the heating element goes to the other. Connections need to be tight and fully insulated. Slide the rubber protective cap back over the reset button.

Run a full test cycle before you pack up and call it done. Tighten your water heater drain plug all the way. Turn on the fresh water supply in your RV and crack open a hot water tap inside. Let water run until it’s flowing steady with no air bubbles—that means the tank is full and air is purged. Shut the tap. Eyeball the new element and all your connections for any drips or leaks.

Switch on the circuit breaker feeding the water heater. Set your multimeter to AC voltage and touch the probes to the element terminals—you should see roughly 120 volts (anything from 110 to 125 is fine). Flip the water heater switch on the interior control panel. Let it run for 30 to 45 minutes on a 6-gallon tank, or 45 to 60 on a 10-gallon tank, until it reaches full temperature. Turn on a hot water faucet and confirm water is coming out hot. Watch that first cycle closely—no weird noises, no smells, no leaks is what you’re looking for.

The Suburban Thermostat Switch That Actually Holds Temperature on the Road

Nine times out of ten when your Suburban water heater won’t stop cycling or completely refuses to warm up, the thermostat switch is the culprit—not the heating element at all. That switch is what signals the heating element when to turn on and off, and once it jams, drifts out of whack, or quits making proper contact, you’re either torching propane like crazy or taking freezing cold showers at sunrise in the middle of nowhere.

What works

• Stays locked on its target temperature—no wild swings between ice-cold and scalding, no constant on-off cycling every few minutes.
• OEM-spec replacement that fits a Suburban 232 series unit without any guesswork on voltage or thread pitch; drops right in and bolts up.
• Kills the propane bleed-through that happens when a faulty thermostat keeps telling the heater to keep running.

What doesn’t

• Some aftermarket swaps have terminal crimps that don’t quite match—you might have to steal the old terminals off your dead switch and move them to the new body.
• Most suppliers are running 5 to 7 day lead times; if you’re remote camping and the water heater’s already down, you’re either waiting it out or paying rush shipping.

I second-guessed myself halfway through the first replacement, thinking the element was actually dead, until the new thermostat brought the tank from lukewarm to 130°F in under an hour. Grab the OEM Suburban 232306 thermostat here.

This post contains affiliate links. As an Amazon Associate, I earn from qualifying purchases at no extra cost to you.