Is Car Underglow Legal? What to Check Before You Install

Underglow is the mod that gets the parking lot asking what kit you run. Before you mount one, answer a different question first: is car underglow legal where you drive?

The short answer is that it depends on your state. In the four state codes quoted below, the rules center on color and on flashing or moving light. Two of them also cover what is fitted to the car, not only what is lit on the road.

This is not legal advice. XKGLOW's own instruction sheet for its XKmax underglow kit puts it plainly: "Please check your local and state laws for the proper use of this product."

What Four State Codes Say About Underglow

Rules vary by state, and the exact wording matters. None of the four sections below uses the word underglow. Each one sets rules for added lights by color, by flashing, or both.

California. Vehicle Code Section 25400 lets any vehicle carry an exterior lamp that emits "a diffused nonglaring light of not more than 0.05 candela per square inch of area." The same section says that light "shall not display red to the front, but may display other colors." Subdivision (c) caps the lamp at 720 square inches of area. Section 25250 adds: "Flashing lights are prohibited on vehicles except as otherwise permitted."

Arizona. Revised Statutes 28-947 covers driving on a highway with certain lamps. The banned lamp is one "capable of displaying a red or red and blue light or lens visible from directly in front of the center of the vehicle." The section continues: "Lights visible from the front of a vehicle shall be amber or white." Subsection C says "flashing lights on motor vehicles are prohibited," outside a short list that includes emergency vehicles and turn signals.

Minnesota. Statutes 169.64 reaches further. It says "no vehicle shall be equipped" with "any lamp or device displaying a red light or any colored light other than those required or permitted in this chapter." Subdivision 3 opens: "Flashing lights are prohibited, except:" and then lists the exceptions.

New York. Vehicle and Traffic Law Section 375, subdivision 41, starts from white. No light "other than a white light" may be "affixed to, or displayed on any vehicle except as prescribed herein." The same sentence bars any "flashing, oscillating or constantly moving white light." The exceptions that follow cover vehicles such as an "authorized emergency vehicle" and a "hazard vehicle."

Small words carry weight here. Arizona says "capable," Minnesota says "equipped," and New York says "affixed." Read your own state's section with that in mind.

What About Blue Car Underglow?

Blue comes up in three of the four codes. Minnesota says "blue lights are prohibited on all vehicles," with exceptions for state road-maintenance and snow-removal equipment and a few listed cases. New York's blue-light paragraph starts with "One blue light may be affixed to any motor vehicle owned by a volunteer member of a fire department," then adds conditions. Arizona names red and blue together for light seen from the front.

What to Check Before You Install Underglow

Do this homework before the kit arrives. These checks shape how you wire and run the lights.

1. Find your state's lighting section. Search your state legislature's site for its vehicle code, or ask your DMV. Look for the words color, flashing, equipped, and affixed. Check city and county rules too.
2. Pick a color for the road. Check which colors, if any, your code allows on a public road. If it restricts red or blue, plan around them.
3. Decide what runs while you drive. Chase themes move by design, and all four codes above restrict flashing. Settle on a steady color the code allows, or nothing at all.
4. Plan where the tubes sit. California bars a diffused light "within 12 inches or in such position as to interfere with the visibility or effectiveness of any required lamp." Keep tubes clear of headlights, taillights, signals, and reflectors.
5. Think through the sensor wires. The XKmax controller has 3 sensor wires that sync the glow with turn signals, brakes, and courtesy lighting. Turn-signal effects flash by nature. Check them against your state's flashing rule too.
6. Budget the time, or book a pro. XKGLOW lists the install at 2 to 3 hours. Its instruction sheet recommends a licensed professional and treats damage from improper installation as voiding the warranty. Prefer a shop? Find an Expert, on the product page, takes you to XKGLOW's dealer locator.

How to Install Underglow Lights on a Car: The XKmax Order

The instruction sheet for the XKmax Underbody Kit lays out a test-first sequence. In short:

1. Plug the tubes together and into the controller and switch harness, connect the battery, and test every light before mounting anything.
2. Disconnect, remove any bodywork that will cover the lights, and clean the mounting surfaces. Tape the tubes loosely in place with painter's tape (not included) and test the chase patterns.
3. Clean again and note each tube's input and output side, since the tubes are directional. Mount them with the 3M tape, using the screw tabs and zip ties where needed.
4. Connect the extension wires and switch harness following the wiring diagram. Never force a plug; check the pins line up.
5. Secure loose wires away from hot or moving parts, mount the ON/OFF switch somewhere dry, and cap any open connectors.
6. If you want sensor effects, tap the sensor wires with the included T-tap connectors. Then connect to 12V power, download the XKmax app, and scan the instruction sheet's QR code to load your kit preset.

To see it done, browse XKGLOW's customer install and review videos or its surprise build on a high schooler's first car.

How XKmax Controls Help You Run Underglow Your State's Way

The standard XKmax kit uses addressable RGBW LEDs, pairing RGB chips with dedicated white chips. Its product page lists it for cars, trucks, Jeeps, and more. The Underbody Kit (MX-CAR-STA) carries eight 24-inch tubes on a 2-channel controller.

The XKmax ULTRA kit (MX-CAR-ULTRA) uses impact-resistant, IP67 aluminum tubes, and XKGLOW rates it 2.7x brighter than its standard XKmax car kit. At list prices as of this writing, the Underbody Kit is $341.99 and ULTRA kits start at $999.99.

Both run on the XKmax app over Bluetooth. The app guide linked from the kit page shows the controls that matter for road use:

• Steady or off on demand. The light-effect wheel shows Solid On and Off next to effects like Left Chase and Center Chase. Pick Solid On in a color your code allows.
• A power-on mode you choose. Default Mode sets what each channel shows when it powers up, so the kit wakes up in the look you picked.
• Zones and brightness. One controller runs up to 10 lighting zones. Each zone takes its own color and brightness. Split the front run into its own zone and it can carry a different color from the sides.
• Off from your phone. The app guide shows how to switch the lights off from a toggle in the app's menu.
• A key fob for quick changes. The programmable 4-button key fob comes with the Interior + Underbody (MX-CAR-ADV) and Interior + Underbody + Wheel (MX-CAR-PRO) kits. You set each button's job in the app.

None of these settings makes a kit legal on its own. They make it simple to run the lights the way the code reads.

Check the Law, Then Build

Read the lighting section, note which colors and effects it allows on the road, and decide what runs while you drive. Then choose the kit and set its power-on mode before the first night out. Underglow is one layer of a full car LED build. Build yours today.

Frequently Asked Questions

Can you drive around with underglow lights on?

It depends on your state. California allows a "diffused nonglaring light" that does not "display red to the front." Minnesota bars "any colored light other than those required or permitted," and New York starts from white. All four codes above restrict flashing. On the road, run a steady color the code allows, or nothing.

In what states is underglow illegal?

None of the four codes above uses the word underglow. The answer sits in each state's color and flashing rules. Minnesota's wording covers how a vehicle is "equipped," and New York's covers any light "affixed to" a vehicle. Check the code where you drive before you buy.

Is installing underglow hard?

XKGLOW lists its XKmax underglow install at 2 to 3 hours. The instruction sheet runs in order: test, plan, mount, wire, and connect to 12V power. It has you tape the tubes loosely and test patterns before fixing anything. For a pro install, use the product page's Find an Expert link to XKGLOW's dealer locator.

Will underglow drain my battery?

It can if the kit stays powered while the car sits. The XKmax app guide gives two ways to cut power. If you drive regularly, switch the lights off from the app's menu. If the car will sit for an extended period, use the physical power button on the wiring harness, which cuts power completely.