Having an issue with your converter fan usually does not involve a bad fan itself.
If your RVs converter or fan is not working, Running a test to troubleshoot your RV converter will verify the true root of the issue. The most likely cause is a bad battery or an issue with a component of the converter itself such as bad fuses or temperature sensors.
Reasons why your RV converter or Fan is not working properly
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Electrical System was overloaded and popped a breaker.
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Batteries are bad and not holding a charge.
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You have a blown converter fuse.
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A Faulty temperature sensor.
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The converter is bad.
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The actual converter fan motor died. (least common cause)
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What does a Converter do in an RV?
The RVs converter has the job of converting 110v AC power to 12v DC power from either shore power or running a generator. Having 12 volt is essential for powering outlets and led lights on your RV. The secondary job is to to act as a charger for the RV batteries.
When it’s working well, it should show an AC voltage reading of 110-130 volts, and a DC voltage at the batteries between 11-13 volts.
Signs of a faulty power converter range from dim or flickering lights, total loss of 12-volt power outlets, a cooling fan that wont stop running, and low battery load. Additionally if the some things can cause your fan to run constantly, which we will get into later in the article.
An Inverter does the opposite of converting 12 volt dc power to 120 volt ac power. This is quite common with systems that integrate with solar panels.
What does a Converter Fan do?
The RV converter fan runs to reduce heat build up. Its runs as needed, and is controlled by temperature and load sensors, to keep the converter from overheating. If the fan fails, the converter will overheat and burn out your converter.
…Before replacing the fan or the whole converter, do yourself a favor and check for other likely causes first.
Tools you will Need
Before you start Troubleshooting you’re going to need a Multi-meter. This is a small tool that pays dividends to own.
Truthfully just about any one will do, you don’t have to buy the most expensive one on the market to get the job done.
That said…
I personally buy items that will last. So if you’re looking for a for a simple, reliable, and still very affordable devise, then the Fluke 101 digital multimeter is what I would recommend for most users. From years of home projects to RV projects this multi-meter has served me well and I still use it all the time.
Why is my Power converter not working? Troubleshooting:
Look for Flipped breakers on your RV or converter, or main electrical panel on our RV
Check for Bad fuses on the converter box. I’ll tell you how to check fuses in this post.
Test input and output voltage for correct load.
Test for low voltage in your batteries. Either your converter is not charging the batteries properly, or the batteries themselves are bad.
Test the Temperature sensor.
\You may have a Bad Battery
One of the most common reasons why an RV converter may not be working properly are bad batteries.
The way to check this is to test the batteries using a multimeter or hydrometer. Disconnect the vehicle from any external power source, such as your generator or shore power.
If batteries are connected in parallel, they should be disconnected from each other so that you can test them individually. (You will be able to know that the battery is connected in parallel by seeing if each positive terminal is connected to the next positive terminal.)
I have tested batteries immediately after disconnecting them and gotten fairly accurate results, but to get the most accurate reading give the batteries 20 minutes to rest.
Use your test meter, and test one battery at a time. it should read around 12.7 volts. If you are not getting max output your battery may need replacement. If the battery is faulty, it is not able to power the converter fan adequately.
If they are low, you can also charge them and give them a few hours, then retest to see if they hold their charge.
If you test the battery and see that it is working fine, then you will want to move on to testing your RV converter and fuses.
Blown RV converter and Fuses
Start by seeing if you fuses are working properly. I use a multimeter to test the fuses. Some peopel will inspect them visually, which works SOMETIMES! But I don’t think that is an reliable way to know if they are good or not.
You’ll also want to test other fuses if you have another panel in your RV. Ill include a video to guide you through the process.
with your multimeter check to see if the converter is getting 110-volt AC power and is outputting 11-13 volts DC. This is to see if the converter is doing its job.
If the breaker for the converter trips, unplug and reset it. If it trips again, you might have a faulty converter.
From personal experience I have found that the batteries and fuses are the most common cuprits and also very easy fixes for power converter problems.
Faulty Temperature Sensors (Advanced DIY’er only)
At this point I woudnt blame you if you just wanted to replace the whole converter with a new one, I think that’s completely acceptable. If you do however want to dig deeper and check the sensors you will need to have the 120-volt power on during this in order to test it correctly.
If you are not 100% confident in your ability to undertake this electrical-component-heavy task, consult an electrician. Working with these components can be dangerous to an untrained hand. Everyone has a different level of skill and comfort about with electricity. A competent electrical engineer could be helpful.
How to Check your Temperature Sensors in your RV converter:
Step 1. First disconnect power from the converter. You will need to unhook from shore power cord, or shut down the generator.
Step 2.Now, remove the case around your power converter. Typically, RV converter manufacturers are not expecting owners to diagnose their own converters. Because of this, the converter case will likely not have visible screws or bolts for you to remove.
Know that if you remove the rivets or spot welds that hold the converter case in place, you may be invalidating your warranty.
Step 3. Once you have the power converter case removed it should not be difficult to find the fan. Inside this case, you should find a solenoid, a number of diodes, the transformer itself ,and a circuit board.
The circuit board monitors and manages the charge to the coach batteries. You may also notice a printed circuit board – this accommodates your capacitor and a number of resistors.
As this is a printed circuit board, be very careful not to damage the printed circuits or any electronic parts as you remove the board to access the fan. However, due to the structure of your converter, you may not need to interact with it to get to the fan.
Importantly, within this box, you will find two AC wires and three DC wires.
Step 4. Restore 120-volt power only to the converter, as you will need it to test out the voltage running to it.
WARNING: there are now live components exposed to the very tight space in which you will be performing these tests.
The fan inside the heat sink is a 120-volt component. That is why you need to to be plugged into shore power.
Step 5. Finally, you were going to test the thermostat/temperature sensor. The temperature sensor is what controls the fan. Using a shrink wrap gun, heat gun, or hair dryer, blow hot air into the heat sink. Use a multimeter to test the amount of power passing to the thermostat as it heats up.
Continue to test it after it is heated, to see if the voltage changes. If you do not see 120-volt power passing from the thermostat after it heats up, then the thermostat or temperature sensor unit is faulty.
Before you replace either component, disconnect the open converter from 120-volt power So you don’t get electrocuted.
Replacement of Converter Fan
Alternatively, if you have gone through this entire troubleshooting process and if what you have found is: 1) the thermostat is functioning, 2) the power is conveyed to the fan, 3) and the fan is not running, then you know the fan motor is bad! You will need to replace the cooling fan.
These are very specific components and may or may not be easily available. Look for the part ID number, and see if you can source out the fan by itself.
If you cant to find a fan replacement. you will need to buy a whole new converter unit for your RV, for which I have a few personal recommendations.