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Why Does The RV Water Pump Make The Lights Flicker?

RV Water Pump Power Usage & Lights Flickering

Out of all of the 12 volt appliances in an RV, the water pump usually is the one that uses the most power when running, around 100 watts.

That doesn’t sound like a lot of power, but for a 12 volt system being run by batteries, it can easily overload the circuit.

The high power draw can cause other electronics that are connected to it to stop working properly.

Like the RV lights flickering.

In this article, I’ll go over some of the common reasons for flickering lights when the RV water pump is running and a few things you can do to try and fix it.

Related Product: Better LED lights like these (click to view on Amazon) can fix the flickering issue right away. 

Reasons an RV Water Pump Can Make Lights Flicker

Power Supply Issues

If your RV electrical system is being run by the RV batteries the flickering lights could be a sign that there’s something wrong with the batteries or the connection.

It could be that the batteries are too low to supply enough power to both the pump and the lights.

The battery terminals could also be corroded. Dirty terminals and connections can reduce the power the battery can supply, causing flickering lights.

A loose ground wire is also another common cause of issues with the 12 volt power system in an RV.

Follow the wires from the batteries and relay to find where the grounding wire is connected to the RV frame. It may have come loose over time.

If the RV is plugged into a power source and the 12 volt pump is still making the light flicker the 12 volt converter in the RV might not be working properly.

See Also: How To Install Solar Panel On RV Roof & Connect To Battery

LED Lights

LED lights are sensitive to voltage change. That means if your 12 volt system is even just a little bit overcrowded or the batteries aren’t supplying enough power, they will flicker.

Also if the LED lights aren’t made to handle different voltages this could damage them and make them go out much faster.

Overcrowded Circuit

A 12 volt circuit in an RV is usually connected to a lot of different appliances. The fans, lights, water pump, and 12 volt TV could all be on the same line.

Each 12 volt circuit is only made to handle a set amount of amps. If the connected appliances start to pull more amps than the circuit is made to supply the highest power draw appliance like the RV water pump will steal power from other devices.

If you’ve recently upgraded the 12 volt fan in your RV to a larger one that draws more power or added a 12 volt TV you may start to see the lights flickering when the water pump is running.

See Also: Best Deep Cycle RV Battery (AGM, SLA, 12V, 6V)

dirty battery terminals cause flickering lights in rv when water pump is running
Dirty battery terminals are a common reason for flickering lights when the RV water pump is running.

Fixes For RV Water Pump Light Flicker Issue

Clean Battery Terminals and Connections

The first thing you can try if the lights have just recently started to flicker is to clean the RV battery terminals and connections.

Cover the terminals and connections in baking soda and spray with water. Wait a few minutes to let the baking soda neutralize the battery acid.

Then, clean the terminals and connections using a soft brush like a toothbrush.

Spray the terminals with a Battery Terminal Protectant (click to view on Amazon) to help prevent future corrosion so the connection stays strong.

Check Ground Wire Connected to RV Frame

It’s not uncommon for the ground wire connected to the RV’s frame to come loose.

Check the frame around the 12 volt relay to find the grounding wire.

If the connection is loose or corroded, it could be causing the voltage drop, making the RV lights flicker.

See Also: Do I Need To Use RV Water Pump When Connected To City Water?

Use LED Lights with Low to High Voltage Range

This is usually the solution to flickering RV lights.

Budget RV LED lights usually have a fixed voltage of 12 volts, it’s one of the reasons they are so budget friendly.

A high quality RV LED light will have a wide voltage range so it can handle the voltage surges and drops that are common in RVs.

You can try changing the lights in your RV with these RV LED Lights (click to view on Amazon) that can handle both low and high voltages 10-24 volts.

Add New 12V Circuit For RV Water Pump

The 12 volt circuit the water pump is connected to can be too overloaded sometimes by other 12 volt appliances.

TVs and larger roof vent fans can easily draw more power than the circuit was made for.

When the RV water pump starts to run it takes all the power from the other appliances and causes everything else on the circuit to stop working.

One way RVers combat this overcrowded circuit issue is to create a new circuit from the RV battery or relay just for the 12 volt pump.

Use an RV water pump controller like this (click to view on Amazon) to make the wiring and adding on/off switches easier.

Have any more questions about the RV water pump making the lights flicker? Leave a comment below.

by Jenni
Jenni grew up in a small town in Idaho. With a family that loves camping, she has been towing trailers since a very young age.

4 thoughts on “Why Does The RV Water Pump Make The Lights Flicker?”

  1. I have this problem in my 12v system when my water pump runs. Lights flicker and my tv shuts off and furnace stops and 12v low voltage alarm goes off. After reading your article I noted I do have an old style (but not too old) green battery shut off switch that sometimes I have to tighten the hell out of just to get any 12v power at all. Should I just eliminated this?

    • Hi Robert,

      It could definitely be what’s causing the issue. I think it’s a good idea to either remove it or replace it with a new one.

  2. Hi Jenni,

    I found this article really helpful as I have the same problem in my van, any appliance that draws high voltage makes my LEDs flicker, it seems to have gotten worse over the past 2 years, probably due to the battery. But I’m a bit confused as to how to create a new 12V circuit for the water pump as my solar charge controller only has one fusebox outlet. Any help / advice is much appreciated.



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