RV Transfer Switch Troubleshooting

RV Transfer Switch Troubleshooting: A 5-Test Guide

Is your automatic transfer switching not working correctly? Is it malfunctioning unexpectedly? You might try searching the internet.

But, here’s the catch:

Whenever you search “ATS Troubleshooting” or “RV Transfer Switch Troubleshooting” on the internet, you’ll find articles that hardly serve your purpose, along with some unanswered forum posts.

Well, don’t worry, we got you covered. We’ll tell you all about RV Transfer Switch Troubleshooting so that you can fix your malfunctioning Automatic Transfer Switch.

In this article, we’ll tell you all about what a transfer switch is, how it works, and the troubleshooting RV transfer switch problems, broken down into 5 different tests.

A Quick Overview

Issues with switches in an RV are more common than you’d expect to face. Transfer switches are no different from facing such issues.

Sometimes your 120-volt devices need to be powered in your motorhome when you’re not plugged in to a campground power supply, also known as shore power.

When this shore power is not available, an onboard generator can provide the necessary power.

So, what’s the hassle here?

Well, now you have to connect the RV’s central power distribution system to two different power supplies, which can be quite a problem if you try hard wiring.

But this can be done quickly with an Automatic Transfer Switch. It acts as a controller between the shore power supply and the onboard generator of an RV.

So how do transfer switches work?

We’ll be exploring that next.

How A Transfer Switch Works

The transfer switch lets the onboard generator run as long as there is not a supply of shore power. But as soon as it detects shore power, it switches to it and turns off the onboard generator.

This helps save generator energy and cuts down a lot of the work for you. Pretty convenient, isn’t it?

Well, here’s what’s crazy:

These ATS systems tend to malfunction sometimes, and that may hamper the whole power system of your RV. Handling that is precisely what we’ll be taking you through along this article.

Some Basic Facts About Transfer Switches

Here are some things you should know:

Transfer Switches sizes: 30-Amp and 50-Amp RV power.

They can have a built-in surge protector. However, some also have EMS under/over voltage protection as well.

There’s usually a 20-40 second delay after the generator starts up. So, you have to wait for a while before the power stabilizes again.

The transfer switch runs on shore power by default unless the generator is on. Moreover, some complex ATS systems can even turn on the generator for you.

So, now that you know the basic facts of a transfer switch, here are some precautionary measures in the next section.

Precautions Before RV Transfer Switch Troubleshooting

Troubleshooting with thermostat, fan, over and several other devices of an RV is a regular incident. An RV owner knows the struggle.

Keep a piece of wood beside you for safety. This way, someone else can help stop electrocution. Wear a pair of slim rubber insulated gloves to be safe.

You’ll be working with an open panel here. So, unless you’re qualified to perform these tests, call an electrician.

Let’s jump right into troubleshooting now.

The Troubleshooting

We have broken down the transfer switch troubleshooting process into 5 different tests so that you can understand transfer switch failure better.

Here goes:

Test 1

Calibrate your meter to 600-volt AC setting and examine incoming shore power between the red and white, black and white, and black and red wires inside your Automatic Transfer Switch box.

When hooked to the pedestal electricity and the circuit breaker for the pedestal is on, it should read around 120-volts AC from white to red and white to black.

It should read about 240-volts in between the black and red wires on the 50-amp service. You probably have a problem with the pedestal, adapters, or cord set, if it doesn’t.

Solution: Get the parts replaced. Some good pedestals, adapters, and cord sets can be found in the market.

Fix that problem before you decide to move on to the next test.

Test 2

In this test, you’ve to start up your RV’s onboard generator. Keep your meter still set to the 600-volt AC scale, test the incoming power from your generator.

It should measure 120 volts between red to white and black to white, while either between 0 volts or 240 volts within black to red, depending on if you wire your generator to be 120/120 volts or 120/240 volts.

Either way, it’s okay, but if you don’t measure any voltage, something prevents the generator from producing power, possibly it’s the circuit breakers.

Solution: Replace your circuit breaker.

See to this problem before you proceed along with the next test.

Test 3

With the generator turned off, calculate the outgoing voltage to your RV’s load center wire. It should weigh precisely the same as the voltages you found in TEST 1 from the pedestal shore power.

If that doesn’t happen, you have a loose connection, or maybe one of the contacts on one of the relays controlling the pedestal energy burned out.

Solution: Fix the loose connection or replace the pedestal relays. You’ll find good pedestal relays online.

Test 4

Start the generator and wait 20 seconds until the controller times out. It would be best if you observe the relay kicking in, showing that the RV power is now coming from the generator.

If it doesn’t do so, then your ATS’s timer circuit has failed. Or maybe, the relay coil has opened up, and you’ll need to repair it.

Solution: Repair the relay coil or replace the timer circuit. You’ll find some good quality timer circuits in the market.

Test 5

With the generator powered up and the relay clicked in, you should now measure the outgoing voltage to the RV’s load center wires. It should read the same energies as Test 2.

If only one leg has 120-volt, but the other has about 0 volts, there might be a burned contact in the generator relay.

In this case, you’ve to change the transfer switch system altogether, unless you can find a replacement relay.

Solution: Find a replacement relay or replace your ATS system. The market has some great ATS systems out now.


That’s all on RV Transfer switch troubleshooting. Following the steps, we just showed you would be enough to get you through with small problems.

If you see that the 5 tests mentioned above aren’t working, call an electrician to help you out.

Now, I’ve got a couple of questions for you.

What kind of problem did you find after trying the tests?

Could you fix it by yourself?

Let us know in the comments below.

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