RVs are little houses riding on moving frames, with shore power, batteries, propane, plumbing, appliances, roof seals, slides and sometimes generators all packed together. That means one symptom can have a very simple cause: a battery disconnect, a tripped GFCI, a winterization valve, a blocked vent, a low propane cylinder, a weak ground or a setup step that got missed after travel.
Use the symptom, not the part name
You do not need to know the part name to start. Choose the closest symptom below, then follow the linked guide or guided troubleshooter. If two symptoms match, start with the one that happened first.
Lights, outlets, batteries or shore power acting weird
RV electrical diagnosis starts by separating 120V AC from 12V DC. Lights, pumps and control boards can fail while outlets still work, or the other way around.
Pump runs, water is missing, or the fresh tank fills itself
Water problems often come from valve position, air on the suction side, a hidden leak, city-water pressure or a check valve that is letting water go backward.
Fridge warm, freezer cold, check light on, or hot-weather cooling trouble
First identify the refrigerator type. Absorption refrigerators, 12V compressor refrigerators and residential refrigerators follow different diagnostic paths.
AC not cooling, furnace won't light, or airflow feels wrong
Climate problems are usually power, airflow, thermostat/control, propane ignition or compressor-load problems. A good timeline matters: what happens first?
No hot water, lukewarm water, or propane/electric mode trouble
Do not heat an empty tank. After that, the big questions are bypass valve position, propane ignition, electric element power and cold-water mixing.
Something heavy will not move or seal correctly
Slides, jacks, awnings and steps need healthy 12V power and clear movement. Stop early if the mechanism binds, twists, grinds or moves unevenly.
The five checks that save the most time
- What changed recently? Travel day, winterizing, battery replacement, propane refill, new campground, heavy rain and storage are all clues.
- Which power source does it need? Many propane appliances still need 12V controls. Many outlets need shore, generator or inverter power.
- Does it fail under load? A battery, ground or connection can look fine until the furnace, slide, pump or compressor actually starts.
- Is a valve, switch or lockout in the wrong position? Bypass valves, battery disconnects, GFCI outlets, resettable breakers and winterization valves create a lot of “broken” RVs.
- Can the system breathe, drain or move? Blocked vents, dirty filters, frozen coils, stuck footpads, packed refrigerators and sealed-over roof openings can all stop normal operation.
When to stop and call a pro
Owner checks are useful, but there is a line. Stop when the repair involves live 120V panels, propane pressure, burner adjustment, brake systems, tire damage, roof fall risk, slide/jack structural binding, damaged wiring, smoke, carbon monoxide, ammonia smell, yellow refrigerator residue, or anything you cannot test without guessing.
FAQ
Why do so many RV problems come back to 12V power?
Because 12V power runs control boards, thermostats, pumps, fans, lights, propane appliance controls, slides and many safety devices. Even when plugged into shore power, the converter and battery path still matter.
What should I write down before calling a mobile RV tech?
Write down the RV year, make and model, the appliance or component model number, what happened first, what works normally, any fault codes, what power source you were using, and any recent repairs or weather events.
Is the guided troubleshooter better than reading articles?
Use both. The troubleshooter is best when you are standing in front of a symptom. Articles are better when you want to understand the system and avoid the same problem later.
Want the fastest path?
Start with the guided troubleshooter if the RV is acting up right now. Use the article library when you want the deeper explanation.
Editorial note
This page is a starting point. Model-specific manuals, safety labels and qualified technicians take priority over general troubleshooting advice. Individual repair pages include more detailed safety limits and system-specific checks.