Reverse Lights Not Working: Reversing Light Faults and MOT
Reverse lights not working? Check the bulb, fuse, earth and reversing light switch. Plus MOT rules and when reversing lights became compulsory in the UK.
In this guide
Reverse lights not working is usually caused by a blown bulb, a blown fuse, a faulty reversing light switch on the gearbox, or a broken wire or earth. If only one light is out, start with the bulb. If both are out, check the fuse and the reverse switch. On cars first used from 1 September 2009, a reversing lamp that does not work is an MOT failure.
This guide covers whether reversing lights are part of the MOT, when they became compulsory (in the UK and, briefly, the US), how to find the fault step by step, and how to fix it and get the retest.
Are Reversing Lights Part of the MOT
Yes, for vehicles first used on or after 1 September 2009. The DVSA MOT inspection manual (section 4.6) says at least 1 reversing lamp must be fitted, it must show a white light to the rear, and it must come on automatically when reverse gear is selected and go off when reverse is deselected. Vehicles first used before 1 September 2009 do not have their reverse lights inspected.
Is a Reverse Light an MOT Failure
Yes. On a vehicle in scope, every one of these is a major defect, which means the vehicle fails:
| MOT defect (section 4.6) | Category |
|---|---|
| A reversing lamp inoperative | Major (fail) |
| Lens defective | Major (fail) |
| Lamp likely to become detached | Major (fail) |
| Lamp not securely attached | Minor |
| Colour or position not as required | Major (fail) |
| Switch not operating as required (not on in reverse, or not off when reverse is deselected) | Major (fail) |
The manual lists “a reversing lamp inoperative” without an exception for cars with 2 lamps, so if your car has 2 reverse lights and 1 is dead, expect a fail. A reverse light that stays on all the time is also a fail, because it is not switching off when reverse is deselected.
What Year Were Backup Lights Required
In the UK there is no single year when every car had to have reverse lights. Car makers fitted them as standard for many years, and the UK rules arrived in stages:
| Date | What changed |
|---|---|
| 1 April 1986 | Under the Road Vehicles Lighting Regulations 1989 (RVLR), any reversing lamp on a motor vehicle first used from this date (or a trailer made from 1 October 1985) must carry an approval mark. Reversing lamps were still classed as optional. |
| 1 September 2009 | Vehicles first used from this date have their reversing lamps inspected at the MOT. |
| 20 May 2018 | RVLR amended to make a reversing lamp obligatory on motor vehicles that type-approval rules require to have one, meeting paragraph 6.4 of ECE Regulation 48. |
So for a UK owner the practical answer is: if your vehicle was first used on or after 1 September 2009, its reverse lights must work to pass the MOT. Older vehicles almost always have reverse lights fitted, and if they are fitted they must be white and approved, but the MOT does not check them.
In the United States, backup lamps are required on new vehicles under the federal lighting standard FMVSS 108, which dates from the late 1960s. US state inspection rules on reverse lights vary, so check your own state’s requirements.
Reverse Light Not Working: Find the Fault
Work from the cheapest, most likely cause to the least likely. You need the correct replacement bulb, a test lamp or multimeter, and someone to sit in the car (or a mirror or reflective window behind you).
Safety first: on a manual car, select reverse with the engine off, the ignition on and the handbrake firmly on. On an automatic, keep your foot on the brake and the handbrake on. Never stand behind a vehicle with the engine running in reverse.
Step 1: One Light or Both
- One reverse light out: the bulb, the bulb holder or the wire to that lamp.
- Both reverse lights out: the fuse, the reverse light switch, or the wiring before it splits to the 2 lamps.
- Car has only 1 reverse light: work through every step.
Step 2: Check the Bulb
Remove the bulb from the rear cluster (usually through an access panel in the boot or by unbolting the cluster). Look for a broken filament or a blackened glass. If you are not sure, test it on a known good holder or with a multimeter on continuity. Most reverse lights use a W16W (921) wedge bulb or a P21W (382) bayonet bulb; our guide to W16W 921 bulbs shows how the wedge type fits.
Step 3: Check the Holder and Earth
Green or white corrosion on the contacts is common, especially where the cluster seal has failed. Clean the contacts with fine abrasive paper or a contact cleaner, and make sure the contacts spring back against the bulb. With the ignition on and reverse selected, use a test lamp across the 2 holder contacts. If you have power on the feed but the bulb still will not light, the earth is poor: trace the black or brown earth wire to its earth point and clean it to bare metal.
Step 4: Check the Fuse
The handbook or the fuse box lid shows which fuse protects the reversing lights. On some cars it is shared with other circuits such as the radio, mirrors or the reversing camera, so a related fault elsewhere is a clue. Replace a blown fuse with one of the same rating. If the new fuse blows straight away, there is a short circuit, often a trapped or chafed wire in the tailgate loom or at the cluster.
Step 5: Test the Reversing Light Switch
The reversing light switch is the most common cause when both lights fail together on a manual car. It is a small 2-wire switch screwed into the gearbox casing, usually on the top or side, with a plunger that is pressed by the selector mechanism when reverse is engaged.
- Find the switch (follow the 2-wire plug on the gearbox; the handbook or a workshop manual will show where).
- Unplug it and check the plug and pins for corrosion or oil.
- With the ignition on, bridge the 2 terminals in the plug with a fused jumper wire.
- If the reverse lights come on, the switch is faulty. If they do not, the fault is in the wiring, fuse or lamps.
- To confirm, test the switch itself with a multimeter on continuity: it should be open circuit out of reverse and closed in reverse.
Replacing the switch is usually a matter of unscrewing it and screwing in a new one with a new sealing washer. Some gearboxes lose a little oil when it comes out, so have a tray ready and check the gearbox oil level afterwards.
Automatic Gearboxes and Modern Cars
On many automatics the reverse lights are switched by the gear selector position switch (often called the inhibitor or range switch), which also stops the engine starting in gear. If the reverse lights fail and the car is also reluctant to start in Park, that switch is the prime suspect. On many newer cars the gear position is read electronically and the body control module switches the lamps, so a diagnostic scan may show a fault code.
Step 6: Check the Wiring
The most common wiring breaks are in the rubber gaiter between the body and a tailgate, where the loom flexes every time the tailgate opens, and at the cluster plug. On vans, tractors and trailers, look for chafing on the chassis, rodent damage and corroded connectors. A light that works intermittently, or cuts out over bumps, is usually a wiring or earth fault.
Reverse Lights Stay On
If the reverse lights stay on with the car in other gears, the switch is stuck closed or the feed wire is shorted to a live wire. Unplug the reverse switch: if the lights go out, replace the switch; if they stay on, look for a short in the wiring. Leaving it means a flat battery and an MOT fail.
Fixing It and Getting the Retest
Most reverse light faults are cheap to fix. A bulb costs a few pounds and takes minutes. A reversing light switch is a modest part, and on many manual cars it is a straightforward screw-in job, although access on some front-wheel-drive cars means working from underneath. Wiring repairs in a tailgate loom take longer.
If your car failed its MOT on a reverse light:
- Take it back to the same test centre by the end of the next working day after the test, and lamps (other than headlamp aim) can be rechecked as a free partial retest.
- If you leave the car at the test centre for repair, a partial retest within 10 working days is also available.
- A car with a major defect can only be driven away if the previous MOT is still valid, and even then it must be roadworthy. A dead reverse light is unlikely to make a car dangerous, but get it fixed promptly.
Replacement reverse lamps and reversing lights for vans, trailers and older vehicles are in our reverse lamps range, and spare blade fuses are in our fuses and fuse holders.
Trailer Reverse Lights Not Working
A trailer reverse light needs a feed from the towing vehicle. On a 13-pin socket that is pin 8. A standard 7-pin 12N socket has no reverse pin, so a trailer on a 12N plug alone cannot have working reverse lights without a 12S socket or a separate feed. Check that the tow vehicle’s socket is actually wired for reverse, because many aftermarket towbar kits leave pin 8 unconnected. Our 13-pin trailer plug wiring guide has the full pin chart, and the trailer lights not working guide covers socket and earth faults.
For more on the law, bulbs and LED upgrades, see our main guide to reverse lights.
Frequently asked questions
Is a reverse light an MOT failure?
Yes, on vehicles first used on or after 1 September 2009. An inoperative reversing lamp, a defective lens, the wrong colour, or a lamp that does not switch with reverse gear is a major defect. Older vehicles do not have their reverse lights inspected.
Where is the reversing light switch?
On most manual cars it is screwed into the gearbox casing, with a 2-wire plug. On automatics the reverse lights are usually switched by the gear selector position switch or by the car’s electronics.
Why have both my reverse lights stopped working?
Both lights failing at once points to the fuse, the reversing light switch or the wiring before it splits to the 2 lamps. Two bulbs rarely blow at exactly the same time.
Can I drive with a reverse light not working?
Reverse lights are not used while driving forwards, but a faulty one on a vehicle first used from 1 September 2009 will fail the MOT, and reversing at night without one is harder and less safe for people behind you. Fix it as soon as you can.
What year were backup lights required?
In the UK, the MOT has inspected reverse lights on vehicles first used since 1 September 2009, and RVLR has made them obligatory on type-approved vehicles that must have them since 20 May 2018. In the US, they are required on new vehicles under FMVSS 108, which dates from the late 1960s.
