License Plate Lights Not Working - Top Causes, Fixes & What to Do

Certified Professional Automotive Mechanic – Owner and Editor of VehicleRuns

Last Updated: November 4, 2026

Safety note: Troubleshooting guidance can help you narrow down likely causes, but it cannot replace an in-person inspection. If the vehicle feels unsafe, warning lights are flashing, you smell fuel, see smoke, notice overheating, or have problems with braking, steering, or control, stop driving when it is safe to do so and have the vehicle inspected.

If your license plate lights are not working, the problem is usually in the bulb, fuse, socket, or wiring feeding the rear lamp circuit. On many vehicles, these lights come on with the parking lights or headlights, so a failure can be as simple as a burnt-out bulb or as annoying as a broken wire in the trunk harness.

This symptom is easier to narrow down when you look at the pattern. If only one plate light is out, the issue is often local to that bulb or socket. If both are out, especially along with tail or marker lights, you are more likely dealing with a fuse, switch, power supply, or body control problem.

This guide helps you sort out the common failure points, what to check first, and when the problem is minor versus when it points to a deeper electrical fault.

Start by noticing whether one light is out or both, and whether the tail lights still work. That split usually tells you whether the problem is a simple lamp issue or a wider circuit fault.

What you notice	Most likely cause	What to check first	Urgency
Only one plate light is out	Burnt-out bulb	Swap or inspect that bulb for a broken filament or dark glass	Diagnose soon
Both plate lights are out	Fuse or power supply problem	Check the fuse for tail, park, or license lamps	Diagnose soon
Tail lights also do not work	Lighting circuit fault	Turn on parking lights and verify fuse, switch, and lamp circuit power	Can worsen
Lights flicker when trunk opens	Broken hatch wiring	Inspect the rubber loom near the trunk or hatch hinges	Can worsen
New bulb still does not light	Corroded socket or bad ground	Check for corrosion, melted contacts, and ground continuity at the socket	Can worsen
Moisture inside the lamp housing	Damaged lamp housing	Remove the lens and look for water, rust, or green corrosion	Can worsen

Best first move: Check whether the parking lights and tail lights work, then inspect the bulbs and the fuse before chasing wiring deeper into the rear harness.

Safety note: The car may still run normally, but driving without plate illumination can be illegal at night. If other rear lights are also out, avoid night driving until the circuit is fixed.

Table of Contents

Most Common Causes of License Plate Lights Not Working

Most license plate light failures come down to a handful of simple electrical faults. Start with these three, then use the fuller cause list later in the article if the obvious checks do not solve it.

Burnt-Out License Plate Bulb: If only one plate light is out, the bulb itself is the most common cause, especially on older incandescent setups.
Blown Fuse or Park Light Circuit Power Loss: When both plate lights are out, a shared fuse or power feed for the parking lamp circuit is a common place to look first.
Corroded Socket or Broken Rear Harness Wiring: Moisture, road salt, and repeated trunk or hatch movement can damage the socket contacts or break wires near the rear body loom.

What License Plate Lights Not Working Usually Means

License plate lights are simple, but they are part of a larger exterior lighting circuit. On many vehicles, they share power with tail lights, side markers, or parking lights. That means the exact pattern matters more than the symptom by itself.

If one side is out and the other still works, the problem is usually local. A bad bulb, corroded socket, or heat-damaged contact is more likely than a system-wide fault. This is especially true when the failure came on gradually or after a bulb flickered for a while.

If both plate lights are out at the same time, think upstream. A blown fuse, failed light switch output, circuit fault, or body control module issue becomes more likely. If other rear running lights are affected too, the problem is usually not the bulbs themselves.

Movement-related clues are useful here. If the lights cut in and out when you open the trunk or rear hatch, the wiring loom near the hinge area is a strong suspect. If you find water inside the lens or white or green corrosion on the terminals, the failure is often at the socket rather than farther up the circuit.

Possible Causes of License Plate Lights Not Working

Burnt-Out License Plate Bulb

The bulb is the final load in the circuit, so once its filament opens, that light stops working even though the rest of the circuit may still be fine. This is the most common cause when only one plate light fails and the other exterior running lights still operate normally.

Symptoms to Watch For

Only one license plate light is out
The failed bulb looks dark or has a broken filament
The other plate light still works normally
The light may have flickered before failing completely

Low Severity

This is usually a minor, isolated lighting fault, though it can still create a visibility or legal issue at night.

How to Confirm: Remove the bulb and inspect the filament and base.

How to Diagnose Car Lighting Problems

Typical fix: Replace the failed license plate bulb with the correct type and wattage.

Blown Fuse or Park Light Circuit Power Loss

Many vehicles feed the license plate lamps from the same fuse or branch circuit as the tail or parking lights. If that fuse opens or the power feed is lost, both plate lights can go dark at once.

Symptoms to Watch For

Both plate lights are out
Tail or marker lights may also be out
The failure may happen suddenly
Bulbs test good but there is no power at the sockets

Moderate Severity

A simple fuse may be easy to fix, but repeated fuse failure points to a short that should not be ignored.

How to Confirm: Check the owner's manual or fuse box cover for the tail, park, or license lamp fuse.

Typical fix: Replace the failed fuse and repair the underlying short or power feed fault if the new fuse blows again.

Corroded License Plate Light Socket

The license plate lamp area sees water spray, road salt, and vibration. Corrosion at the socket contacts raises resistance or opens the circuit entirely, so the bulb may not light even when power is present.

Symptoms to Watch For

Bulb is good but does not light
Green, white, or rusty buildup in the socket
Intermittent operation after rain or washing
Socket contacts look burned or pushed back

Moderate Severity

This is usually localized, but corrosion tends to worsen and can eventually damage the connector or blow the fuse.

How to Confirm: Remove the bulb and inspect the socket closely with a light.

How to Diagnose Car Lighting Problems

Typical fix: Clean minor corrosion or replace the socket and pigtail if the contacts are damaged or heat-stressed.

Broken Rear Harness Wiring

Wires that pass through the trunk lid or rear hatch flex every time it opens and closes. Over time, the copper strands can break inside the insulation or the insulation can crack, causing an open circuit or intermittent plate light failure.

Symptoms to Watch For

Lights flicker when the trunk or hatch moves
Both lights may cut in and out together
Other hatch-mounted electrical items may act up
The problem is worse in cold weather or after repeated opening

Moderate to High Severity

The plate lights themselves are minor, but harness damage can spread to other rear electrical functions and may eventually short out.

How to Confirm: Pull back the rubber loom near the trunk or hatch hinge and inspect the wires for cracked insulation or broken strands.

Typical fix: Repair or replace the damaged wire section and properly seal and support the harness.

Bad Ground at the Rear Lamp Circuit

A poor ground can stop the plate lights from working even when power is available. High resistance at a body ground or connector can also cause dim or intermittent lighting, especially if moisture has gotten into the connection.

Symptoms to Watch For

Bulbs test good but stay dark or glow weakly
Lights may flicker or act oddly with other lamps on
Ground point shows rust or looseness
Voltage is present on the power side but the circuit will not complete

Moderate Severity

A ground fault can affect multiple lights and often worsens over time as corrosion spreads.

How to Confirm: With the lights on, test voltage at the socket and perform a voltage drop test on the ground side.

Typical fix: Clean and tighten the ground connection or repair the faulty ground wire or connector.

Damaged License Plate Lamp Housing or Lens

A cracked lens, warped housing, or failed seal can let water into the lamp area. That leads to bulb failure, corroded contacts, and sometimes heat damage or partial shorts inside the housing.

Symptoms to Watch For

Visible moisture or water droplets inside the lens
Repeated bulb failures in the same location
Cracked, loose, or missing lens pieces
Corrosion returns soon after cleaning

Moderate Severity

The immediate issue is usually minor, but water intrusion often creates repeat electrical problems until the housing is fixed.

How to Confirm: Remove the lens or housing and inspect for cracks, broken seals, and signs of water tracks.

How to Diagnose a Foggy or Moisture-Filled Headlight

Typical fix: Replace the damaged lamp housing, lens, or seal and install a fresh bulb if needed.

Lighting Control Module or Switch Circuit Fault

On some vehicles, exterior lights are not powered directly through a simple switch. A body control module, lighting control module, or switch circuit may command the plate lights, and a fault there can leave the lamps off even when bulbs and wiring appear intact.

Symptoms to Watch For

Both plate lights are out with good bulbs and fuse
Other parking or tail light functions are also inconsistent
No power reaches the rear lamp circuit despite a good fuse
The issue may appear after electrical work or battery problems

Moderate to High Severity

The car may still drive normally, but module-controlled lighting faults usually need more involved diagnosis and can affect other exterior lights.

How to Confirm: Confirm the bulbs, fuse, socket condition, and rear wiring first.

How to Diagnose Sensor Circuit Faults

Typical fix: Repair the failed switch circuit, reprogram if applicable, or replace the faulty lighting control module.

How to Diagnose the Problem

Turn on the parking lights or headlights and confirm whether the license plate lights should be on in that mode.
Check whether one plate light is out or both, and note whether the tail lights and side markers still work.
Inspect the bulbs first. Remove them and look for a broken filament, darkened glass, or corrosion on the base.
Check the fuse for the tail, park, or license lamp circuit using the fuse chart and a test light or meter.
Look closely at the license plate lamp sockets for green corrosion, melted plastic, loose contacts, or water intrusion.
If the bulbs and sockets look decent, test for power and ground at the socket with the lights switched on.
Open and close the trunk or rear hatch while watching the lights. If they flicker, inspect the wiring loom near the hinge or flex point.
Inspect the lamp housing or lens for cracks, missing seals, or signs of water getting inside.
If there is power loss and the fuse is good, trace the circuit back toward the rear connector, switch, or control module.
If multiple rear running lights are affected and basic checks do not find the problem, move to wiring-diagram diagnosis or professional electrical testing.

Can You Keep Driving if the License Plate Lights Are Not Working?

Important: The guidance below is general and cannot confirm that your specific vehicle is safe to drive. If a symptom affects braking, steering, handling, fuel, overheating, smoke, visibility, or vehicle control, treat it as potentially serious and have the vehicle inspected before continued driving when appropriate. For more context, see our Automotive Safety Disclaimer.

A license plate light failure usually will not strand you, but it does matter for night visibility and legal compliance. Whether you can keep driving depends mostly on whether this is an isolated plate lamp issue or part of a larger rear lighting failure.

Okay to Keep Driving for Now

Usually okay for short-term daytime driving if the car operates normally and all other rear lights work. You should still fix it soon, especially if one bulb is already out and the other may be aging too.

Maybe Okay for a Very Short Distance

Maybe okay for a very short trip if only the plate lights are out but the tail lights, brake lights, and turn signals still work. Avoid night driving if local laws require plate illumination and visibility is poor.

Not Safe to Keep Driving

Do not keep driving at night if the failure is part of a wider tail light or running light problem. If fuses keep blowing, wiring is heating up, or multiple rear lights are dead, stop and repair the electrical fault first.

How to Fix It

The right fix depends on whether the problem is at the bulb, the socket, the rear harness, or the shared lighting circuit. Start with the simple checks, because many license plate light problems are solved without deeper electrical repair.

DIY-friendly Checks

Replace the bulb, check the relevant fuse, clean light corrosion from the socket, and inspect the lens for water intrusion or obvious damage.

Common Shop Fixes

A shop will often replace a corroded socket or pigtail, repair broken hatch wiring, or trace an open or short in the rear lamp circuit.

Higher-skill Repairs

Module-controlled lighting faults, wiring-diagram tracing, and repeated fuse-blowing shorts usually need more advanced electrical testing and repair.

Related Repair Guides

Typical Repair Costs

Repair cost depends on the vehicle, labor rates in your area, and whether the issue is just a bulb or a deeper wiring fault. These are typical U.S. parts-and-labor estimates for common fixes.

License Plate Bulb Replacement

Typical cost: $10 to $50

This usually applies when the fix is simply replacing one or two standard bulbs with easy access.

Fuse Replacement and Basic Circuit Check

Typical cost: $20 to $90

This range fits a simple blown fuse and a quick check to make sure there is no obvious recurring short.

License Plate Light Socket or Pigtail Replacement

Typical cost: $80 to $220

Cost rises when corrosion has damaged the connector and the wiring needs to be spliced in.

Rear Hatch or Trunk Harness Wire Repair

Typical cost: $120 to $350

This is common when wires break inside the flex loom and labor is needed to expose and repair them properly.

License Plate Lamp Housing or Lens Replacement

Typical cost: $70 to $250

Typical when water intrusion, cracked plastic, or broken mounting points caused repeat failures.

Lighting Module or Switch Circuit Diagnosis and Repair

Typical cost: $150 to $600+

This usually reflects diagnostic time plus a switch, module, or programming-related repair on vehicles with electronic lamp control.

What Affects Cost?

Whether the failure is just a bulb or a wiring repair
Ease of access to the license plate lamp assembly
Trunk or hatch harness labor time
OEM versus aftermarket housing or connector parts
Whether module diagnosis or programming is required

Cost Takeaway

If only one light is out, expect the cheaper end of the range and start with the bulb or socket. If both are out, especially with other rear running lights affected or flickering with hatch movement, costs usually move into fuse, harness, or module diagnosis territory.

Symptoms That Can Look Similar

Parts and Tools

FAQ

Can a Fuse Cause Both License Plate Lights to Stop Working?

Yes. On many vehicles both plate lights share a fuse or a branch of the parking light circuit. If both go out together, the fuse is one of the first things to check.

Why Did My New License Plate Bulb Still Not Work?

If a new bulb does not light, the next likely problems are a corroded socket, no power at the lamp, or a bad ground. A damaged housing that lets in water can also keep causing the same failure.

Do License Plate Lights Come on with Headlights or Parking Lights?

Usually yes. Most vehicles power the license plate lights with the parking or tail lamp circuit, so they should come on when the exterior running lights are on.

Can Broken Trunk Wiring Affect the License Plate Lights?

Yes. On hatchbacks, SUVs, and some sedans, repeated trunk or hatch movement can break wires inside the rubber flex loom. That often causes intermittent or total loss of plate lights.

Is It Illegal to Drive with License Plate Lights Out?

In many places it can be, especially at night. Even if the car drives normally, a dark plate can lead to a fix-it ticket or failed inspection, so it is worth repairing soon.

Final Thoughts

Most license plate light problems are narrowed down quickly by looking at the pattern first. One light out usually points to a bulb or socket, while both out pushes you toward the fuse, shared circuit, or rear wiring.

Start with the simple checks you can see and test easily, then move deeper only if the bulbs and fuse are good. The symptom is often minor, but if other rear lights are involved, treat it like a broader electrical fault rather than just a burnt-out lamp.