RV Lights And AC Not Working | Explained

Having your RV lights and AC simultaneously stop working can be incredibly frustrating, especially if you are mid-trip and relying on these systems. I also have gone through the same situation once, so I can understand your pain.

The problem typically stems from power supply problems like a depleted battery, faulty converter, or tripped circuit breaker cutting off electricity to both systems. Methodically troubleshooting connections, fuses, breakers, and wiring faults, and testing voltage at key points will help isolate the root cause.

Knowing how to troubleshoot and repair these systems can save you the time, money, and headache of having to take your RV into the shop. For this, I’ll help you explore the most common causes of RV lights and ACs failing at the same time in this guide and provide actionable tips to diagnose and address the problem yourself.

RV Lights And AC Not Working

Why RV Lights and AC Often Fail Together

There are a few key reasons why the lights and AC commonly stop working in tandem:

  1. Power Source Issues: If your RV is not connected to shore power or the generator is not running, the 12V battery is the only power source. Once discharged, the battery cannot power your 120V AC and 12V DC lighting systems.

Loose or corroded battery connections also cause high resistance, resulting in voltage drops. Inspect terminals and cables for any corrosion buildup or greenish oxidation and clean thoroughly.

  1. Short Circuit in Wiring: Faults in wiring like chafed insulation and loose connections can create shorts in the 12V and 120V systems, cutting power to lights and AC. Shorts from chafed or pinched wires can blow fuses interrupting 12V DC current flow. Severe 120V AC shorts trip breakers. Inspect wires near access openings and moving parts for damage. Shorts cause hot spots that can melt insulation and catch fire.
  2. Converter/Inverter Failure: The converter converts 120V AC shore or generator power to 12V DC to charge batteries and power lights. If it fails, 12V DC devices lose power. The same for the inverter, which converts battery DC to AC for the air conditioning.
  3. Breaker Tripping: The master breaker that feeds all your RV circuits could trip due to overloads. Resetting may temporarily restore lighting and AC power until overloaded again. The cause could be faulty 120V appliances, loose/damaged wiring, insufficient service capacity, etc. The AC may overload and trip the breaker by itself.
  4. RV Appliance Limbo: Some RVs have a fuse that cuts power to AC appliances when connected to shore power. If it mistakenly trips, the AC will not turn on.
  5. AC Unit Malfunction: If AC power is present but your RV air conditioner fails to start up, the issue may be within the unit itself – bad START capacitor, blower motor stuck/burned up, control board failure. RV AC repair services can troubleshoot and identify internal AC faults.
  6. Rodents Chewing Wires: Mice and other rodents are attracted to the insulation on wires for nesting material. Their chewing can sever wire circuitry. Look for any signs of nesting, droppings, or teeth marks in electrical boxes and conduits to identify and seal up access holes.

Now let’s explore these issues in more detail and how to diagnose and fix them.

Step-by-Step Diagnosis and Repair

When your RV lights and AC fail in tandem, systematic troubleshooting is key to isolate the cause. Here is a step-by-step approach:

Step 1: Check the Battery Charge and Connections

Start by visually inspecting your 12V battery. Look for any corrosion or loose connections on the terminals that could impede current flow. Use a multimeter to check the charge level. The battery should read 12.6V or higher when fully charged.

If the battery charge is very low, jump-starting or recharging may restore power to get the lights and AC going temporarily while you continue diagnosing.

Step 2: Inspect the Shore Power Hookup

For shore power, examine the connection to your RV electrical inlet. Make sure the plug is fully inserted and locked. Wiggle it to check for looseness that could cause intermittent power loss.

Look for damaged, melted, or corroded contacts and pits in the receptacle that prevent full plug contact. Plug a voltmeter into the inlet to confirm 120V power – if not, the issue is on the supply side.

Step 3: Check the Generator

For generator power, ensure fuel tanks are filled. Attempt starting – no startup, starter issues, or sudden shutdowns point to generator problems. Verify generator breakers are switched on.

Check that 120V power outputs properly from the generator to the RV by testing receptacles. If shore and generator power are both absent, there is an issue distributing power in the RV electrical panel.

Step 4: Turn Off All Circuits and Reset Breakers

Flip all breakers off and then on again to reset the electrical system. Then switch on just the lighting circuit and AC circuit one by one to isolate any overloads or short circuits.

If flipping either one trips the breaker again immediately, that points to a wiring issue in the respective system.

Step 5: Check 12V Fuses and Breakers

With all 120V power off, inspect the fuses in the 12V fuse panel. Look for any that are burned or blown then test circuits with a new fuse. Also, reset 12V breakers by switching to “off” and then back to “on”.

If blowing fuses or tripping breakers point to shorts in 12V wiring powering lights. The converter could also be overheating and triggering its internal over-temp breaker.

Step 6: Test Voltage Converting Components

Use a multimeter to check the converter and inverter outputs. Plug shore or generator power in. The converter output should show around 13.6V DC. The inverter input should be 12V DC from the battery and output 120V AC.

No or low outputs indicate a faulty converter or blown inverter fuses. Check manufacturer specs for target voltage ranges. If converters/inverters test faulty, they will likely need replacement.

Step 7: Inspect Your Main Electrical Panel

Check for any signs of blackened/melted wires, burned insulation, or buzzing/sizzling indicating arcing shorts. Loose or corroded bus bar connections can also cause intermittent power loss throughout the whole RV.

Remove cover panels to check for nesting insects or rodents that may have chewed through wires. Any signs of heat damage or chewed wires point to damaged feeder wiring from the electrical panel circuits.

Step 8: Evaluate AC Unit and Thermostat

Ensure the AC breaker is on – if tripped, identify and resolve overloads. Verify the thermostat settings by lowering to max cold. Use a multimeter to test voltage at the AC unit – no power indicates an issue along the wiring, not the unit itself.

Check fuses/breakers in the AC unit electrical box then test components for faults. Inspect the condenser and evaporator coils for damage or clogs. Diagnosing issues inside the AC itself is best left to an HVAC technician.

Step 9: Test Known-Good Appliances

For lights, plug a simple 120V device like a phone charger into interior outlets. If it doesn’t turn on, power is not reaching the outlets. Do the same for a 12V circuit like your vehicle socket using a phone car charger.

This isolates whether the issue is in the wiring feeding the particular lights/AC, or if the power source itself is compromised and not energizing any circuits.

By methodically testing these key components and locations, you can effectively isolate the root cause and zero in on where the specific electrical fault is occurring. Safety first – turn off all circuits any time you are inspecting electrical systems with panels removed.

Fixing RV electrical issues requires basic tools like a voltmeter, screwdrivers, and wire cutters/strippers. For serious AC repairs, system rewiring, or electrical component replacement, consult a certified RV technician to avoid hazards.

Tips to Prevent RV Electrical System Issues

While RV electrical problems will crop up occasionally, you can take proactive steps to reduce instances of lights and AC failing:

  • Maintain batteries – Check fluid levels monthly. Clean any corrosion on terminals. Equalize flooded batteries every 6 months.
  • Limit high-draw appliances – Microwaves, hairdryers, and too many AC units on at once can overload circuits.
  • Plug into shore power whenever possible – Avoid exhausting batteries which strain the electrical system.
  • Inspect exterior seals – Ensure all external conduit openings and roof-mounted AC vents and exhaust are well-sealed to prevent water damage or rodent entry.
  • Exercise generator monthly – Run under load to keep it in good operating condition for backup power needs.
  • Hire an electrician annually – Have them inspect connections, wiring, and components for any damage. Replace deteriorated cords/cables.
  • Install surge protectors – Use the pedestal to protect from external voltage spikes.
  • Keep an electrical toolkit – Equip your RV with basic tools like a voltmeter, spare fuses, crimpers, wire cutters, etc.

When to Call an RV Technician

While many electrical issues can be resolved yourself, it’s best to involve a professional RV technician for:

  • Diagnosing complex wiring faults in 120V/240V systems
  • Accessing and repairing components in AC units
  • Major appliance diagnosis and repair
  • Installing new converters, inverters, transfer switches, etc.
  • Rewiring RV electrical systems
  • Assessing shore power pedestal electrical issues
  • Evaluating generator repair needs
  • Ensuring repair work meets RV electrical safety standards

Look for certified and experienced RVIA/RVDA/ASE master-certified technicians. Research tech background, experience, and shop reviews. Get an estimate beforehand and clarify the service warranty.

While an RV technician visit may cost over $100 per hour, their expertise resolves issues faster and provides peace of mind that repairs meet codes. They also have professional tools and testing capabilities beyond a basic multimeter.

For serious electrical problems, the potential hazards make professional diagnosis and repair well worth the cost. You will have the correct fix to restore lights and AC promptly so you can get back to your travels.

Related Queries

What Are The Signs Of An Electrical Short Circuit In My Rv?

Symptoms of a short include:

  • Frequently tripped breakers
  • Burned-out/blown fuses
  • Flickering or dimming lights
  • Burning rubber smell
  • Warm electrical boxes/conduit
  • Shock from touching appliances

Why Did My Ac Stop Working But The Lights Are Fine?

Possible causes specific to a non-working RV AC unit:

  • AC circuit breaker tripped
  • Failed AC contactor switch
  • Burnt out air handler blower motor
  • Broken thermostat
  • Clogged AC filters or condenser coils

How Much Does It Cost To Repair Rv Electrical System Issues?

Costs vary based on the issue:

  • Fuse or breaker replacement: $10-$30
  • Wiring short repair: $200-$400
  • Converter replacement: $200-$400
  • Inverter replacement: $800-$1,500
  • Professional diagnostics: $100/hr shop rate


Oftentimes, the problem stems from battery or wiring faults that can be repaired yourself. More complex electrical issues like converter/inverter failure or AC unit malfunction may require professional service. But with a logical diagnostic approach, you can identify the problem area so any repairs stay focused. Your RV adventures are meant to be fun and comfortable. Don’t let frustrating electrical problems put a damper on creating lasting memories. Hopefully, this guide has equipped you to methodically troubleshoot the underlying issue. Safe travels and hopefully your electrical systems provide reliable performance down the open road. Please leave a comment below if you have any other helpful tips or questions!

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