How To Tell If Your RV Converter Is Bad

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Traveling across the country in your RV is one of the most exciting things you could get yourself into. But what if your RV converter starts to act strangely in the middle of the journey?

You wouldn’t be able to enjoy all the convenient devices that require 12V DC current to operate. Cameras, smartphones, laptops – you just wouldn’t be able to charge them! Thereby, you better make sure that everything is okay with your RV converter before the journey.

Now, we’ll help you understand how to tell if your RV converter is bad.

Signs that your RV converter went bad

The RV converter performs badly

This is the first sign that your converter is bad.

Most commonly, this happens because the converter produces insufficient power to run its 12-volt direct current electrical system. In this case, the converter’s 12V batteries can no longer retain a constant charge. For the RV converter to work, its batteries need to maintain a constant charge to be able to supply current.

You would want to spot issues with batteries as soon as possible. One bad battery that is unable to hold its charge would draw power from good batteries. Eventually, the good batteries would also go bad, and you would need to replace them all instead of just one. Unfortunately, if you don’t do occasional testing, you won’t spot a battery issue until they all go bad and lose their charge.

How to test the batteries

To check the condition of your batteries, you need to fully charge them and then disconnect them from each other. If you keep them connected, the bad batteries will draw charge from the good ones, and you will have a hard time spotting charging issues.

After the disconnected batteries sit for some time, check the charge in each of them using a multimeter. Faulty batteries won’t be able to maintain a constant charge, as we already mentioned.

The voltage range is abnormal

Another sign that your RV converter went bad is abnormal voltage ranges. This may happen in either the entry point where 110V AC supply enters the RV converter or in the 12V DC breaker box.

At the entry point, the voltage should be between 108 and 130 volts. Anything in this range is within normal. As for the 12V breaker box, the 11 – 13V range is satisfactory.

How to test voltage

To test the voltage at either the 110V AC entry point or 12V DC breaker box, you need a device called a voltage meter. First of all, check the voltage at the entry point to see whether it is in the normal range. Then, check the voltage at the DC breaker box. If either of them (or both) show bad readings, then you’ll know where the problem most likely comes from.

The cooling fan isn’t working

A malfunctioning cooling fan is another giveaway that your RV converter is operating badly. The fan runs on 110V AC voltage intermittently when the RV converter’s temperature reaches a certain point. If the entry voltage to the converter is incorrect, then the fan most likely won’t work at all.

In the sense of voltage, the fan is indicative of voltage issues at the 110V entry point of the RV converter. However, it may also be that it is the fan itself that is actually malfunctioning.

How to test the fan

Before thinking about replacing your RV converter’s fan, you need to make sure that the problem lies in it. Therefore, do a voltage test at the entry point of the converter.

If there are issues with the voltage, then you will need to resolve them first. Replacing the fan when there are voltage issues is pointless since it most likely won’t work.

After resolving issues with the voltage, you still need to keep an eye on the fan. It is possible that both the 110V line and the fan have gone bad, requiring you to replace the fan as well.

If there are no issues with the voltage in the 110V line, then you can definitely say that the problem is with the fan.

The problems with the cooling fan could lie not in the fan itself but in its thermostat or thermal sensor. Normally, the current runs through the thermostat or the thermal sensor to the cooling fan. If the current doesn’t run past them, the cooling fan won’t operate.

To check whether the thermostat/thermal sensor is working, check whether current is getting past them or not. If not, then you’ll know that they are faulty. At this point, you should also check if the fan is not malfunctioning as well. To do that, you could try to supply it with current directly bypassing the thermal sensor. If the fan starts up, then you won’t need to replace it. Otherwise, you’ll need to replace both the thermal sensor and the fan.

Replacing the cooling fan of an RV converter isn’t a too difficult project. The problem lies in finding a fan that will work with your RV converter. Ideally, you would want to get the exact same fan. To do that, find out the make, voltage, and any other information on the fan so you find a replacement.

You could use another fan though if you have difficulties with finding the same one. Another fan should work as long as it runs on the same voltage and amperage. Besides, it needs to be of the right size to fit in the RV converter.

Where problems with your RV converter can come from

The RV converter itself

Most commonly, problems come from the converter itself. So before you proceed on to checking your accessories and power source, you need to test the converter.

Describing the signs of a bad RV converter, we’ve already provided you with some tips on how to test it. However, the causes of all those seemingly simple problems can lie much deeper than you would want.

Let’s now list the components that you need to check in your RV converter.

The circuit board

The circuit breakers on the circuit board of the RV converter could be one reason for the problem.

To access them, you need to open the circuit breaker panel. Then, open all circuit breakers, starting from the primary input breaker, and examine them. Check if they work and also assess their condition. After you are done examining the circuit breakers, close them in reverse order, ending with the primary input breaker.

The next step is to disconnect the 110 AC power from its pedestal, remove its electrical panel, and check its backside. If there is accumulated acid on the connector tabs or the wire terminals, you could clean it up with a mixture of 1 teaspoon of baking soda with 12 ounces of water. Before reassembling the panel, make sure that all its surfaces are completely dry.

Keep in mind that the accumulated acid could indicate more serious problems that can’t be resolved by cleaning.

Resistors & diodes

Some power converters use resistors to control the voltage of the 12V DC electrical system and the onboard batteries. Normally, it should read between 3 and 13 volts when tested with a multimeter, depending on the battery charge and which onboard accessories are being used. A faulty resistor is often the cause of the batteries being unable to charge.

In some RV converters, the resistors are relatively easily accessible. But sometimes, you may need to disassemble the converter box to access the resistors and even remove the circuit board. Needless to say, you will need to be very careful with the electrical components of the RV converter.

A diode is a component that allows the flow of current in only one direction, at the same time blocking current in the other direction. This crucial electrical component is also rather difficult to test, even for those who have the knowledge and experience.

You can assume that the resistor gates are malfunctioning if you spot a white acid residue in the power converter. In this case, you will most likely need to replace the entire RV converter.

Overall, because of their complexity, maintenance of resistors and diodes should only be done by people who have adequate experience and knowledge of electricity.


The fuses – devices used to protect electrical systems against excessive current – may be another source of the problem. Thankfully, fuses are typically easy to access, so testing them with a voltage tester and replacing them should be an easy task.

Your accessories

Your RV converter may seem completely dead, but it may actually be your accessories that have gone bad. Before starting to look up replacement RV converters, you need to make sure that your DC accessories are intact. It is possible that the issue, in reality, lies in them rather than in the RV converter.

Check if your DC devices receive current from the RV converter. If not, then the problem most likely is in the converter. However, to make sure that it’s not actually your accessories that are faulty, check whether the converter outputs DC current.

The 110V power source

It may actually also be that the problem lies within the 110V power source that you’ve hooked the RV converter into. An easy way to test the power source is to connect it with the 110V appliances in your RV like the microwave or a refrigerator.

If you find that they work with no problems, then your RV converter has most likely gone bad. Otherwise, the problem may be in the 110V power source.

Also, don’t exclude the possibility that it is your appliances that are faulty. In this case, you would need to test whether the 110V power source outputs current with a voltage meter.

Tips on troubleshooting your RV converter

Identify the source of the problem

If you suspect that your RV converter has gone bad, your task is to identify where the problem is coming for. As we’ve just mentioned, the issues with your converter could be caused from within the converter itself, by your DC devices, or the 110V power source.

Buying an entirely new RV converter is a big investment since converters can cost several hundred dollars. At the same time, the problem may actually require you to spend just a couple of dollars on a new fuse. Thereby, you need to find the cause of the issues with your RV converter.

Comprehensively test your electrical devices

Your RV converter could be acting funny for a variety of reasons. But what if there are actually several causes for it? What if there are several components that are faulty? Or what if both the RV converter and the power supply are dead?

Needless to say, you would need to resolve all those issues to be able to use your RV converter for its purpose.

Suppose that the fan and the thermal sensor in your RV converter are faulty. You test the thermal sensor, see that it doesn’t work, and assume that it is the cause for the problems. And you don’t bother to test the fan. You replace the thermal sensor, but the cooling fan still doesn’t work!

You would obviously do some new testing. Eventually, you’d discover that the fan itself is dead. However, you would have spent more time than necessary to fully fix your RV converter. Had you completely checked the RV converter, you would discover all the issues and resolve them in one go.

Hopefully, you now understand why it is crucial to test all your electrical devices before deciding what to do.

Address a professional if necessary

If you find that all this stuff is too convoluted for you, you should probably address a professional. He will have the experience and knowledge to deal with your problem.

What if you, as an individual who doesn’t have much experience with electrical devices, attempt to repair your RV converter and break something else in the process? You would need to spend more money on repairing it than initially! Thus, if you are not sure what you are doing, just address a professional.

Troubleshoot your RV converter before your trip

You don’t want to face an issue with your RV converter in the middle of your journey, do you? So before beginning your trip, make sure to do all the testing at home. Should any issue arise, you would be able to resolve it without rushing.