What to check before you panic — and when to call in a pro
Whether you’re on the road or parked in your driveway, electrical issues in your RV can go from frustrating to dangerous if you don’t know what you’re looking for. From dead outlets to flickering lights, most RVs operate with two electrical systems — 12-volt DC and 120-volt AC — and when something goes wrong, it can be hard to know where to start.
This guide will walk you through the most common RV electrical issues, what you can safely check yourself, and when it’s time to call a certified technician like Murphy Mobile RV Repair.
Understanding Your RV’s Two Electrical Systems
Before troubleshooting, it helps to know the basics:
- 12V DC (Direct Current):
Powers your lights, water pump, fan, and control boards for your furnace, fridge, and more — even when you’re not plugged in. - 120V AC (Alternating Current):
Powers your microwave, air conditioner, wall outlets, and appliances when plugged into shore power or running a generator.
Many issues stem from confusion between the two systems, so knowing which one powers what can save a lot of guesswork.
1. RV Lights Are Dim or Flickering
Likely a 12V issue
Possible causes:
- Weak house batteries
- Poor ground connection
- Corroded or loose wiring
- Failing converter (the device that charges your batteries from shore power)
✅ What to do:
- Check battery voltage (12.4–12.6V is ideal when fully charged)
- Look for corrosion on battery terminals
- If connected to shore power, check if the converter is putting out ~13.6V
- If the lights brighten when the engine or generator runs, it’s likely a converter or battery issue
2. Some Outlets Aren’t Working
Usually a 120V issue, often simple
Possible causes:
- Tripped GFCI outlet (like a home bathroom outlet)
- Tripped breaker in your panel
- A faulty inverter or loose connections behind the outlet
✅ What to do:
- Press the reset button on any GFCI outlets
- Check the breaker panel (labeling can be inconsistent in RVs)
- Plug a lamp or small appliance into the outlet to verify
- If only one or two outlets are out, it’s likely wiring behind that outlet
If you smell burning or see discoloration, call a pro immediately.
3. Fridge, Furnace, or Water Heater Not Powering On
12V controls, 120V operation — it’s complicated
These appliances often rely on 12V power to operate their control boards, even though they use propane or 120V AC to actually run.
Possible causes:
- Dead or weak battery
- Blown fuse
- Bad thermostat or control board
- Tripped the safety switch or ignition lockout
✅ What to do:
- Check the fuse panel (look for blown 15A–30A fuses)
- Verify you’re getting power to the appliance
- Make sure your battery isn’t below 12V
- If the appliance clicks or lights briefly, then shuts off, it may be a safety sensor issue
4. AC Won’t Turn On or Trips Breaker Immediately
High power draw = high stress on your system
Possible causes:
- A faulty capacitor or compressor
- Weak shore power connection
- Dirty coils or clogged airflow
- Overloaded circuit (especially on 30-amp service)
✅ What to do:
- Turn off other large appliances (microwave, water heater)
- Try a different power source or cord
- Let the AC sit for 10 minutes and try again
- If it keeps tripping instantly, call a technician — forcing it could fry the system
Pro tip: Consider a Soft Start or Easy Start upgrade if this happens often on 30-amp setups.
5. Your Battery Keeps Dying — Even When Plugged In
This one’s more common than you think — and usually misunderstood.
Possible causes:
- Faulty converter not charging the batteries
- Bad battery (even new ones can be defective)
- Something is draining power constantly (parasitic draw)
- Shore power not supplying voltage to converter
✅ What to do:
- Test converter output while plugged in (~13.6V at battery terminals)
- Disconnect the battery overnight and check for voltage loss
- Look for always-on items (propane detectors, stereo memory, etc.)
When to Call Murphy Mobile RV Repair
If you’ve checked the basics and something still doesn’t feel right, it’s time to call a professional. Electrical issues can go from inconvenient to dangerous — fast.
We offer on-site RV electrical diagnostics throughout Orange County, and we’ll walk you through what’s working, what’s not, and what needs fixing.
Call (714) 450-5086 or book a mobile electrical inspection today.