What you need to know before you start

The 2018 Prius Prime has two license plate lights mounted on the rear bumper, one on each side of the plate. You can replace both bulbs yourself in about 15 minutes with no special tools — just a Phillips head screwdriver and the correct replacement bulb. The job is straightforward enough that most owners handle it without a dealer visit.

The 2018 Prius Prime uses a 194 LED bulb for the license plate lights. You can find these at any auto parts store, Walmart, or online for $5 to $15 per bulb. LED bulbs last much longer than the older incandescent versions and draw less power, so they're worth the small extra cost upfront.

Key Takeaways

  • The 2018 Prius Prime license plate lights use 194 LED bulbs, available at any auto parts retailer for under $15 each.
  • You need only a Phillips head screwdriver to remove the light housing; no special tools or dealer equipment required.
  • The entire job takes about 15 minutes and involves removing the housing, twisting out the old bulb, and installing the new one.
  • LED bulbs are the better choice for replacement because they last longer and use less power than incandescent bulbs.

Locate and access the license plate light housing

Open your trunk and look at the inside of the rear bumper cover, directly behind where the license plate sits. You'll see two small rectangular housings, one on each side of the plate opening. Each housing is held in place by a single Phillips head screw visible from inside the trunk.

Unscrew that single fastener on whichever side you're working on first. The entire light housing will pull straight out toward you. You don't need to remove the bumper cover itself — just this one small assembly.

Remove the old bulb and install the new one

Once the housing is out, you'll see the bulb socket at the back. Grasp the bulb firmly and twist it counterclockwise about a quarter turn. It will come free in your hand. Don't force it; if it feels stuck, wiggle gently while twisting.

Insert the new 194 LED bulb into the socket and twist clockwise until it stops. You'll feel a slight resistance when it seats fully — that's normal. Push the housing back into the bumper opening and reinstall the screw. Repeat on the other side if both lights need replacement.

Test the lights before closing the trunk

Before you finish, turn on your headlights or parking lights and have someone stand behind the car to confirm both license plate lights are working. If one doesn't light up, remove that housing again and check that the bulb is twisted in fully. A bulb that's not quite seated all the way won't make contact.

If the bulb is seated correctly but still doesn't light, the socket itself may be damaged or corroded. In that case, the housing assembly will need to be replaced as a unit — a dealer can do this, or you can order a replacement housing online for $30 to $60 and swap it using the same single screw.

Why LED bulbs are the better choice

The original incandescent 194 bulbs in older Prius models burn out every 1,000 to 2,000 hours of use. LED 194 bulbs last 30,000 hours or more, which means you may never need to replace them again. They also draw about 80 percent less power, which is a small but real benefit to your battery in a hybrid.

LED bulbs cost more upfront but pay for themselves through longevity alone. They also produce a whiter, brighter light that's easier for other drivers to see. The only downside is that some LED bulbs are slightly dimmer than incandescent ones if they're low quality — stick with name brands like Sylvania, Philips, or GE to avoid this.

What to do if you're uncomfortable doing this yourself

If you don't want to open your trunk and work with fasteners, any tire shop, quick-lube, or Toyota dealer can replace the bulbs for you in under 10 minutes. Expect to pay $20 to $50 in labor, plus the cost of the bulb itself. Some shops will install a bulb you've already bought; others will sell you one and install it as part of the service.

Call ahead and ask whether they charge a flat fee or an hourly rate. Many independent shops offer this as a quick courtesy job and won't charge labor at all if you buy the bulb from them.

Frequently Asked Questions

Can I use a regular incandescent 194 bulb instead of LED?

Yes, incandescent 194 bulbs work fine and cost less upfront — usually $2 to $5 each. However, they burn out much faster and will need replacement every year or two if you drive regularly. LED is the better long-term choice.

What if I buy the wrong bulb size?

The bulb won't fit into the socket, so you'll know when ready. Take it back to the store and exchange it for a 194. Always confirm the bulb number on the package before you leave the counter.

Do I need to disconnect the battery before replacing the bulb?

No. The license plate light circuit is low-voltage and low-power. You can safely work on it with the battery connected and the car off. Just make sure the lights are turned off before you start.

Will the check engine light come on if the license plate light burns out?

No. The Prius Prime doesn't monitor the license plate lights, so a burned-out bulb won't trigger any warning lights. However, a non-functioning license plate light is illegal in most states, so replace it promptly.