RV Lights Flicker when Pump is Running? (Solved!)

While out in your RV, the lights may have that annoying flicker when you switch on the pump.

This is not always limited to the older RVs but can happen with the new ones too.

It is not normal for the lights to dim or flicker. There is an underlying problem when this happens.

What causes this dimming and flickering? How do you go about fixing it? These are probably some of the questions you may have when this happens.

This post explains why you may have flickering lights in your RV, what checks you can perform to identify the fault, and also provides tips that can help you fix it.

Why your RV lights may flicker when the pump is running

#1. Voltage drop in the RV’s battery bank

The light may flicker or dim momentarily because of a temporal voltage drop when the pump starts.

At startup, the current draw by the pump can be substantial resulting in a momentary voltage drop that causes the lights to dim before lighting steadily.

#2. Loose wire connections

Another possible cause of dim or flickering lights is loose wire connections. A loose wire connection at the pump, battery, or where the battery cables connect to the service panel can cause dimming and flickering of the lights as the pump runs.

What Should you Check if the Lights Flicker?

If the lights flicker when the pump is running, check:

#1. Do the lights flicker when the appliances are being powered by the battery bank or shore power?

If it is with the battery bank, your battery capacity or battery bank voltage may be low.

Use a good quality voltmeter to check the battery bank voltage. If they flicker with shore power then you might have a problem with the wiring, probably a loose wire connection.

#2. Do the lights flicker with the pump only or when other appliances in the RV are switched on?

If the lights flicker when only the pump is running and on shore power, you may have to review the sizing of the wiring used. Undersized cables can result in voltage drops that cause the lights to dim and flicker as the pump cycles on and off.

Additionally, if the pump and lights are wired to the same electrical circuit, you may have to install them on separate circuits.

#3. Confirm that the wire connections at the battery and service panel are firm. If the chassis is used as the return or ground connection, inspect the wire connections to the chassis and make sure they are clean and firmly connect to the chassis.

Simple Tips to Stop and Prevent the Lights from Flickering

If the lights in the RV flicker when you switch on the pump, check the following:

#1. Inspect all the wire connections both the positive and ground wires at the battery, pump, and the circuit supplying power to the lights.

Tighten any loose connections and check if the flickering stops when you switch the pump on.

#2. Have you added any additional appliances to the battery? Additional appliances when switched on increase the power draw from the battery that can trigger a detectable voltage drop that makes the lights dim.

First, switch off the appliances, run the pump again and check if the lights still flicker. If they do not flicker with the appliances off then you should consider increasing the battery capacity.

#3. The condition and voltage of the batteries. If the battery voltage is low then the lights can flicker. Charge the batteries and check if the problem persists.

Additionally, if the batteries are old and are not able to hold a charge then the lights may flicker before going off.

Closing Thoughts

If your lights dim or flicker when the pump is switched on and running, it may be that the battery voltage is low or there are loose wire connections at the battery, service panels, or ground connections.

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