You put the car in reverse, glance at the screen and get nothing. Maybe it's a black box, maybe it says "No Signal", or maybe the picture is there but it's so fogged up you can't make out the kerb.
It's easy to assume the camera has died. Sometimes it has. But a lot of the time the fault is somewhere else: a fuse, a damaged wire in the boot lid, a dirty lens, or a setting that got reset when the battery went flat. Those are much cheaper fixes than a new camera, so it's worth checking them first.
This guide covers the faults we see most often, what usually causes each one, and how to tell when the camera itself needs replacing.
Start with the easy checks
Before you take any trim off, rule out the simple stuff.
Clean the lens. Road grime, salt and water spots build up quickly over winter, and a dirty lens can make a working camera look broken. A soft cloth and a bit of glass cleaner is enough.
Restart the screen. Infotainment systems crash like any other computer. Turn the ignition off, open and close the driver's door so the system fully shuts down, wait a few minutes and try again.
Check the settings. Some cars let you switch the rear camera off in the display menu. It's also common for the camera setting to reset after a battery change, a jump start or a software update.
Check the fuse. Your handbook will tell you which fuse covers the camera or the reversing lights. A blown fuse is a two-minute fix, but if it blows again straight away there's a short somewhere that needs finding.
Black screen or "No Signal"
If the screen switches over when you select reverse but shows no picture, the display is doing its job. The problem is the camera or the wiring between the camera and the screen.
On hatchbacks and estates, the tailgate wiring is the first place we'd look. The cables run through a rubber gaiter between the body and the boot lid, and they bend every time the boot opens. After a few years, the copper inside can crack even though the outside of the wire looks fine. The camera often works with the boot in one position and cuts out in another, which is a good clue.
Water is the other usual suspect. Connectors near the number plate and inside the tailgate can corrode, especially if a seal has failed. Unplug the connector, look for green or white corrosion on the pins, and clean or replace it as needed.
If the camera has power, a good earth and an intact video cable but still gives no picture, the camera has most likely failed.
The picture works, but the screen doesn't switch over in reverse
This one is usually about the reverse signal, not the camera. The screen needs to know you've selected reverse, and on many cars it gets that from the reversing light circuit or the reverse light switch on the gearbox.
A quick test: put the car in reverse and ask someone to check the reversing lights. If they're not coming on, the switch or the circuit is the problem, and that also means an MOT fail, so it needs fixing anyway.
On newer cars, the reverse signal often comes through the CANBUS network instead. If you've recently changed the head unit or had other electrical work done, a faulty interface or a coding problem can stop the switch-over even when everything else works.
Flickering, rolling or lines across the picture
An unstable picture nearly always points to power or earth trouble. Look for a loose connection, a corroded earth point or a wire that's rubbing through.
Aftermarket cameras wired into the reversing lights can flicker on cars with monitored lighting, because the car pulses the bulb circuit to check it. The fix there is usually a small relay or power filter so the camera gets a steady supply. We cover this in more detail in our guide to fitting a reversing camera.
Foggy, blurry or water inside the lens
If cleaning the outside doesn't help and the picture looks misty, check for moisture behind the lens. Once the seal on a camera fails, water gets in, and you'll often see condensation or droplets on the inside of the glass.
Some people have luck drying a camera out, but the seal is still broken, so the fog usually comes back with the next cold morning or car wash. In most cases replacing the camera is the only lasting fix.
A blurry picture can also mean the lens is scratched or the coating has worn away. Again, that's not something you can repair.
Upside down, mirrored or missing guidelines
A picture that's flipped, mirrored or missing its parking guidelines is almost always a settings or coding problem, not a hardware fault. It tends to happen after a new head unit is fitted, after a battery disconnect, or when a replacement camera hasn't been set up for the car.
Many aftermarket cameras have a small loop of wire you can cut to flip the image, so check the instructions. On factory systems, the guidelines may need the car's settings adjusting or the camera coding with diagnostic equipment.
Works one day, not the next
Intermittent faults are frustrating because the camera always seems fine when you go to look at it. Pay attention to when it fails. Cold, wet mornings point towards moisture in a connector or a failing seal. If it cuts out when the boot is open or after you've closed it hard, look at the tailgate wiring. If it fails over bumps, there's probably a loose connector somewhere along the route.
How to tell if the camera is the problem
The most reliable test is to confirm that power, earth and the video connection are all reaching the camera. If they are and you still get nothing, the camera is at fault.
If you're comfortable with a multimeter, you can check for 12 volts at the camera connector with reverse selected. If you're not, an auto electrician can test this quickly. Please don't start probing random wires in the boot, especially on newer cars, where you can damage other modules.
Replacing a factory reversing camera
Many factory cameras are made for a specific car. Some sit in the number plate light panel, some are built into the boot handle, and some have connectors that only fit one model range. A universal camera won't always plug straight in.
The best way to find the right part is the part number on your old camera, or the OEM number for your car. If you're not sure, send us your VIN or the part number and we'll help you find the right one. You can browse our reversing cameras here, including replacement boot handle cameras and adapter cables for when you've changed the head unit.
On some cars, a new camera works as soon as it's plugged in. On others, it needs coding or calibrating so the guidelines line up properly. It's worth checking this before you start, so you know whether you'll need a trip to a garage with the right diagnostic kit.
When to get some help
Most of the checks above only need a cloth, the handbook and a bit of patience. Once you're into tracing wiring, testing circuits or coding modules, it makes sense to get an auto electrician involved. They'll find a broken wire in the tailgate loom much faster than you will, and a repair to the existing wiring is often cheaper than a new camera.
And while the camera is out of action, the old way still works: mirrors, a look over your shoulder, and taking it slowly.
This article is a general guide only. Every vehicle and camera system is different, so always follow the manufacturer's instructions, and if you're unsure about any electrical work, speak to a qualified auto electrician.