RV Generator Troubleshooting

RV Generators provide the 120 volt power that facilitates much of the home-like conveniences we enjoy in our RVs.  When they don't work, it can cause a lot of discomfort and frustration.  Here are some of the most common generator related problems and how you can often fix them in the field.

Not plugged in.  Surprisingly, one of the most common problems is a generator that is not plugged in.  Some RVs, especially high end models, have automatic transfer switches that automatically connect the generator to the RV power panel whenever the generator is running.  Also you need to be aware there is usually a short time delay between when the generator starts and when the transfer switch gives access to it.  That is to allow the engine on the generator a chance to stabilize before putting a load on it.  On RVs that do not have an automatic transfer switch you have to plug the RV shore power cable into an outlet connected to the RV generator.  A surprising number of users, especially new or novice users, fail or forget to perform or check this very basic connection before calling a service technician.   All too often the user simply forgot to plug the cord into the generator receptacle.  Sometimes the cord plugged into the generator receptacle some how comes loose.  You should always check the power cord before calling for help.  Obviously, if the problem is that the shore power isn't plugged in it is very easy fix to plug it in.  Along that line, some people forget to plug in shore power at RV parks or fail to check to see if it has gotten unplugged and then complain to park management that the power at their site isn't working.  Always make sure you are securely plugged in before calling for help.  Sometimes your shore power cable may get accidentally unplugged or you might even be the victim of vandals who unplug power cables just for malicious fun.

Tripped circuit breakers.  RVs have a 120 volt power panel with circuit breakers, similar to the one in your home.  If some parts of the RV have power and others don't, this is where the problem likely is.  Resetting a tripped breaker usually solves the problem.  If it keeps tripping you need to find out what extra load is on that breaker and remove it.  In rare cases, a breaker may get worn or weak and trip before reaching its normal load, but tripped breakers are usually caused by users putting too much load on the circuit.  Adding things like electric heaters or other appliances is one frequent source of overloads.  A breaker that pops immediately and consistently often indicates some kind of short or other overload in the electrical system that needs to be corrected.  Simultaneous use of high wattage appliances on the same circuit is often the cause of tripped breakers.  It is OK to attach multiple appliances to the same circuit, like a microwave oven and a toaster, but try not to use them at the same time to avoid overloading the circuit and tripping the breaker.  Frequent overloading of a circuit and tripping the breaker can weaken the breaker and it will need to be replaced.

Generator breakers.  Generators have their own built in circuit breakers.  If you lose power throughout the RV all at once, a tripped breaker on the generator is the most likely culprit.  Some generator breakers are clearly marked and easily recognized.  However, some have markings that are hard to locate or hard to see and the breakers may look like ordinary toggle switches.  In either case, locating and resetting the breaker(s) usually solves the problem.  The breakers will trip if the total demand from the power panel exceeds the rating of the breaker.  Normal use of an RV shouldn't exceed the power rating but sometimes added equipment may cycle simultaneously causing a spike in demand and tripping the breaker.  A one time failure needs only to be reset.  Repeated failures indicate some kind of continuous overload that needs to be diagnosed and eliminated.  I once thought I had a transfer switch problem because I had trouble finding the tripped breakers on the generator.  The labels had been obscured by dirt and oil and the breakers were toggle switches out of sight on one end of the generator instead recognizable breakers up front where I could easily see them.   On this generator the labels were near the right front bottom corner of the generator where they had gotten covered with oil and dirt and the breakers were located near the front bottom corner of the right hand end (not the front) of the generator, with little room next to them and impossible to view.  I needed to use a mechanic's mirror to see them so I could verify which way was on and which was off in order to reset them.

Generator shuts down during use.  RV generators are powered by gasoline, diesel, or propane engines.  Obviously they will shut down if they run out of fuel.  The fuel taps in the fuel tanks for the generators are usually placed higher than the taps for the engine or other appliances so running the generator won't run you out of fuel and leave you stranded.  If your generator shuts down while running, the first thing you should check is the fuel level.  On gasoline powered vehicles the generator tap is usually placed at about 1/4 of the tank to leave you enough fuel to hopefully drive to a filling station once the generator runs out of fuel.   Propane generators run on liquid propane from the bottom of the tank.  Propane appliances, like stoves, furnaces, and water heaters, run on gaseous propane from further up in the tank.  For that reason, generators will not run from the popular "Extend-a-Stay"setups that attach extra, external propane cylinders to the system.  A second reason for generators to shut down while running is low oil.  Most generators have sensors that detect low oil and shut the engines down before they are damaged by lack of lubrication.  If your generator shuts down and your fuel supply is adequate, check the oil level.  If it is low, bring it up to the full mark before attempting to restart the generator.  Sometimes overheating can cause the engine to shut down.  You are most likely to experience this during hot summer days running the roof A/C but it can occur at other times.  Check to make sure there is nothing blocking the air vents to the generator compartment.  One more possible fuel related problem is clogged fuel filter or a failed fuel pump.  You might be able to remove a clogged filter and blow backwards through it to clean out some of the debris to buy you a little more time but clogged filters should be replaced as soon as possible.  Attempting to operate the engine without a functioning fuel filter may cause expensive damage to the engine.  A failed fuel pump will have to be replaced.  If you are a fairly good DIY mechanic you should be able to replace it yourself on site if you can get a replacement.  Most of the generators I've worked on used electric fuel pumps.  Be sure to check the power and verify there isn't a blown fuse.  In a pinch you might be able to use just about any after market electric fuel pump from an automotive store to replace a bad pump on a generator.  A third reason for generators to shut down is over heating.  Many generators are air cooled so make sure the air flow around the generator is not restricted.  Never use the generator compartment for extra storage.  If you happen to have a liquid cooled generator, make sure the coolant level isn't low and make sure the radiator isn't damaged or blocked and that radiator hoses aren't collapsed or clogged.  If you are in unusually dusty conditions or your air filter hasn't been properly maintained, a clogged air filter can create problems.  Cleaning or replacing the air filter should easily solve such problems.

Proper operating and maintenance procedures will minimize generator problems.  Religiously follow the schedule for oil and filter changes, both air and fuel.  Check the oil before each trip and often during between uses.  Clean or replace the air filter per the recommended schedule or more often if operating in dusty conditions.  Check the coolant level and radiator hoses on liquid cooled units before operation.  Make sure there is adequate ventilation for air cooled models.

A surprising number of calls to mobile RV mechanics for generator problems are due to simple user errors that  don't really require a technician.  If you don't have an automatic transfer switch, make sure your shore power cord is plugged in to the generator receptacle.  Check for low fuel or low oil if your generator shuts down.  Regularly perform routine maintenance such as changing the oil and replacing oil, air, and fuel filters to minimize failures and maintain performance.

Power up!