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Fix Your Fluorescent Light Ballast

Two days before Thanksgiving I walked into our laundry to wash my underwear and noticed the light wasn’t working.

After a short three-word phrase (use your imagination) I started to have flashbacks about what led to this moment in time.

First, our laundry room light was struggling to turn on for several days prior to this.

Then it just stopped working altogether.

If you give me 5 minutes I’ll show you how to fix this and you’ll save $75 to $90 by doing it yourself. Let’s get started!!


Getting Started: How to Check that Your Fluorescent Light Ballast is Broken

You’ll only need three kinds of tools for this project:

One clue that your ballast is the reason for a non-working fluorescent light is the light bulbs struggle to turn on.

As I said in the intro, we noticed this happening over a 3-4 week period.

A good way to check that your ballast is the culprit is to turn on a voltage detector and hold it next to the wires supplying power to the ballast.

Test Ballast for Power

If power is going into the ballast and none is flowing to the fluorescent light bulbs this is an indicator the ballast is dead – unfortunately much like the cool old guy named Blue in Old School (for all you Will Ferrell fans, Blue the character dies while, ahem, wrestling!!)

RIP Blue

How to Remove Your Old Ballast and Light

Before doing anything further, turn off the circuit that supplies power to the light.

Then double-check that no electricity is running to the light by using your voltage detector. Many thanks to Mark for reminding me that I forgot to add this SUPER IMPORTANT tip.  But that’s why I have great fans like you who catch my absent-mindedness!!!!

There are only a few screws holding the ballast to the fluorescent light.

Remove these screws using a screwdriver but don’t toss them in the garbage. Primarily because you may not get news screws with the new ballast.

You can choose to remove the ballast before or after you remove the fluorescent light from the ceiling.

To avoid having shattered glass all over the floor I highly recommend removing the fluorescent light bulbs. They’re attached to the ballast and you’ll have to detach the plug.

Removing Fluorescent Light Bulb

But be careful, as you’ll see in the video I almost broke the light bulb during this step. I’m such a dummy sometimes.

Only two screws hold the fluorescent light to the junction box. Use a screwdriver to loosen these screws and just be aware that the light will drop slightly from the ceiling.

Junction Box Screws

Slide the light’s frame and pull it down off the junction box screws.

At this point take a picture of the existing wiring. This will give you a reference and help with wiring the new ballast.

Take a Picture of Wiring

If you’re not particularly strong or have weak shoulders get a friend or relative to help with this part.

Have them hold the light while you unwire the ballast from the junction box. Or, if you really don’t like electricity or your friend/relative (just kidding) you can hold the light instead and let someone else unwire it.

Loosen all the wire nuts. I like to take apart the black or hot wires, then the white or neutral wires, and lastly the ground. It just makes me feel better to do it in this order.

Pull the ballast wires out from the frame.

That’s how simple it is to remove a fluorescent light ballast.

Adding a New Ballast to Your Fluorescent Light

You’ll need to take your old ballast with you to the hardware store. It’s a good idea to call and see if they have the right ballast in stock.

I called around to several places that didn’t have the ballast I needed. And in fact, I still ran into a bit of trouble with the ballast I bought (I explain at the end of the video).

Place the new ballast on the fluorescent light’s frame and tighten it with the screws that you saved from the old ballast.

New Ballast

Fish the new ballast’s black, white, and green wires through the hole in the light.

Get your friend or relative to hold the light while you wire it to the junction box. Seriously, I had to call my wife into the laundry room to help. I felt bad that she had to hold the light up while I fiddled with the wires.

But, hey that’s what marriage is all about — helping each other through DIY sickness or health!!

If you have kinked wires like in the picture below cut them with your combination strippers and strip off 3/4 of an inch of the insulation.

Trim Kinked Wires

Wire the new ballast in the same fashion as the old one. This time around I recommend wiring the ground first, then neutral (white wire), and lastly the hot wire (black in color).

Twist the wire nut until the connection between the wires from the ceiling and the ballast are secure.

Push all the wires back into the junction box as neatly as possible.

Slide the fluorescent light frame onto the screws you left in the junction box. Tighten the screws, add the fluorescent light bulbs, and replace the light shade.

BAM!!!! You’re done.

Here’s my step-by-step video tutorial for your viewing enjoyment. It’ll show you just how easy it is to replace a ballast, or at least I hope so!!

If you can change out a light switch or outlet you can definitely replace an old ballast that doesn’t work.

As I said in the beginning, you’ll save yourself $75 to $90 doing this fix yourself. Years ago I paid our electrician to do a similar fix at a rental and this is how much the fee was.

Rightfully so, too!! But I like saving money for the grocery list that seems to grow every week.

What’s Next

If you’re installing other electrical devices we have several tutorials on how to wire a light switch, how to wire a dimmer switch, and how to install GFCI outlets in bathrooms.

If you’re doing a bathroom remodel and need help, join one of our online courses – they’ll make your bathroom renovation much easier!

Let me know if you have any questions and I’ll do my best to help.

Thanks as always for reading, watching, and being part of our awesome community.



Fix Fluorescent Light Ballasts