Why is my reverse parking light not working?

The most common causes are a blown bulb, a blown fuse, or a faulty reverse gear switch. Start with the basics (bulb and fuse) and then move to the switch and wiring if the problem persists.

What reverse parking lights do and why they fail

Reverse parking lights illuminate when the car is shifted into reverse, signaling others behind you and helping you see obstacles at low speed. They are usually part of the tail light cluster and are activated by a switch or sensor tied to the transmission. When they fail, it can be a quick fix or a sign of a broader electrical issue in the tail-light circuit.

Common causes

Several issues show up most often. If you notice the reverse light is out, these are the first things to consider:

• Burned-out or faulty bulb in the taillight assembly (or an LED module failure).


• Blown fuse or a faulty fuse for the reverse light or taillight circuit.


• Faulty reverse light switch on the transmission or gear selector, which fails to signal the lights to turn on.



• Water intrusion or moisture causing corrosion or short circuits inside the tail-light housing.


• Faulty tail light control module or body control module in vehicles with CAN-bus systems.

In many cars, the backup light circuit is independent from the brake and park light circuits, but some models share fuses or modules. If one side fails, diagnose that specific side first, then check the overall tail-light system.

How to diagnose the problem at home

Use these steps to identify whether the issue is mechanical, electrical, or related to the vehicle’s sensors or control modules. Always prioritize safety and disconnect power before handling electrical components when necessary.

1. Verify the symptom: confirm the reverse light does not illuminate when shifting into reverse, and check if the same bulb also powers other lights in the tail cluster (to rule out a shared circuit issue).


2. Inspect the bulb or LED module: remove the tail light cover and visually inspect the bulb or LED array for a broken filament, darkened glass, or scorch marks. Replace if damaged with a known good part.


3. Check the fuse(s): locate the reverse light or taillight fuse in your vehicle’s fuse box using the owner’s manual. Replace any blown fuses with the correct amperage fuse and re-test.


4. Test for power at the socket: with the car in reverse (engine off and parking brake engaged if advised by the manual), use a test light or multimeter to see if voltage appears at the bulb socket. If you have power, the issue may be the bulb or socket; if not, the problem is upstream (switch, wiring, or module).


5. Inspect wiring and connectors: check behind the tail light for damaged, pinched, or corroded wires and loose connectors. Look for signs of water damage or rust on grounds and connectors.


6. Examine the reverse light switch: on many cars, the switch is mounted on the transmission. Inspect the switch for physical wear, loose mounting, or a faulty contact. Some vehicles have a gear-select sensor in the transmission or a wiring harness connection that can fail.


7. Check for ground integrity: ensure the tail light housing has a solid ground to the chassis. A poor ground can prevent the bulb from lighting even if power is present.


8. Consider vehicle electronics: if no power issue is found and the bulbs and fuses are good, a fault code may exist in the body control module. A scan tool can read codes related to lighting control.

If you complete these checks and still cannot identify the fault, the issue is more likely to be with wiring, a switch, or the vehicle’s control module, which may require professional diagnostics.

What to tell a mechanic

Providing clear information helps speed up the repair. When you visit a shop, share these details:

• Make, model, and year of the vehicle, and whether the issue is on one side or both sides.


• Whether the reverse lights work intermittently or never light up in reverse.


• Results of your basic checks: bulb condition, fuse status, and whether there was power at the socket during testing.


• Any recent work on the tail lights, wiring, or the transmission area that could be related.


• Whether fault codes were read with an OBD-II scanner and what they indicated.

Mechanics may perform further steps such as testing the reverse light switch with a multimeter, inspecting the rear light assembly for moisture, or reprogramming modules if needed.

Repair options and when to consider them

Repairs range from quick bulb or fuse replacements to more involved wiring or module work. Typical scenarios include:

• Bulb replacement or LED module replacement within the tail light housing.


• Fuse replacement, and inspection of the fuse panel for related circuits.


• Repair or replacement of a faulty reverse light switch or transmission sensor.


• Repair of damaged wiring, connectors, or grounding points behind the tail light.


• Software update or module replacement if a body control module or lighting control unit is at fault.

For modern vehicles, some repairs may involve reprogramming or module adaptation, which is best handled by a dealer or qualified technician.

Preventive tips

Regular checks can prevent future failures. Consider these practices:

• Inspect tail lights during routine vehicle maintenance and after big trips or off-road use.


• Replace bulbs promptly when one fails to avoid overloading other bulbs in the circuit.


• Keep tail light housings clean and dry to prevent moisture-related corrosion.


• Use dielectric grease on electrical connections to deter corrosion and improve grounding.


• When you replace components, verify compatibility with your vehicle’s electrical system and check for any fault codes that may arise.

If in doubt, consult a professional to avoid electrical shorts or further damage to the vehicle’s lighting system.

Summary

A non-working reverse parking light is most commonly caused by a blown bulb, a blown fuse, or a faulty reverse-gear switch. A systematic home diagnosis—checking bulbs, fuses, wiring, grounds, and the switch—covers the majority of cases. If power is present at the socket but the light still won’t illuminate, the issue is likely the bulb, socket, or a module/wiring fault. When in doubt, a professional technician can perform deeper diagnostics with specialized tools and ensure safe, compliant repair.

What causes reverse light not to come on?

First check that the bulbholder and wiring terminals are clean and bright. If there is any corrosion, clean it up with wet-or-dry paper then refit the bulb and retest. If the bulb still fails to light, the fuse may have blown. You should also suspect a blown fuse if two reversing lights go together.

How much does it cost to fix reverse lights?

Reverse light bulbs are one of the least frequently employed lights on your car and often last much longer than other bulbs, even to 150,000km and beyond before requiring replacement. It's an inexpensive task, usually costing around $15 to $55 to replace, although some specialty models can be costlier.

Why are my rear parking lights not working?

If your rear parking lights aren't working, the most common issues are a blown fuse, a bad bulb, or a corroded/loose socket. You should check these step-by-step, starting with the fuse, then the bulb, and finally inspecting the socket and wiring. 
1. Check the fuse 

• Locate the fuse box for your vehicle, which is usually under the hood or behind a panel on the dashboard. 
• Find the fuse for the tail or parking lights, often labeled "Tail," "Park," or "Marker" lights. Check the owner's manual for the exact location. 
• Pull the fuse out and visually inspect it for a broken or burnt metal strip. 
• If the fuse is blown, replace it with a new one of the same amperage. 

2. Inspect the bulb

• Access the tail light bulb by removing the tail light cover, which is often done from the trunk or by unscrewing the housing from the back. 
• Carefully remove the old bulb and check its filament for a break or a grayish/blackish color. 
• Replace the bulb with a new one, making sure to clean your hands or use a cloth to avoid getting oil on the new bulb's glass. 

3. Check the socket and wiring 

• Inspect the bulb socket for corrosion or damaged pins. 
• If you see corrosion, clean the contacts with fine sandpaper. 
• Make sure the bulb is seated securely and the connections are tight. 
• If both the fuse and bulb are good, the issue could be with the wiring. Check for any signs of damage or loose wires, especially near the bulb socket and in the main harness. 

When to seek professional help

• If you have replaced the fuse and bulb and the lights still don't work, there may be a more complex electrical issue with the wiring or a faulty light switch. 
• At this point, it is best to consult a professional mechanic for diagnosis and repair. 

Is it illegal to have one reverse light out?

By law a reversing light is classed as an optional light and not an obligatory light, therefore there is no requirment to have oner at all. However it goes on to state that if you do have an optional light fitted then it must comply with regulations which merely state, 1.