Keeping the Eyes Open: A Seasonal Routine for Driver-Assist Cameras, Sensors and Plates

A 2026 family hatchback will typically carry four or five cameras, a forward-facing radar unit, up to a dozen ultrasonic parking sensors and, increasingly, corner radar behind the bumper skins. None of these components announces itself. All of them can be quietly compromised by a film of road salt, a smear of wax, or a number plate that has turned the colour of grey porridge.

The hardware nobody notices

Begin with where the kit actually lives, because most drivers clean around it without realising it is there. The forward camera sits behind the windscreen, usually in the pod behind the interior mirror, looking through a patch of glass that is easy to forget. The radar hides behind the front badge or a smooth panel in the grille. Ultrasonic sensors are the small painted discs set into the bumpers — often body-coloured, which is precisely why they get polished, waxed and scrubbed like any other panel. Reversing and 360-degree cameras sit under the tailgate handle, in the door mirrors and occasionally in the grille.

Every one of those surfaces is optical or acoustic. They do not benefit from the same treatment as paintwork, and some of them are actively harmed by it.

Clean paint is not the same as a clear lens

A car can look immaculate and still be telling its computers that it cannot see. Traffic film on a camera lens scatters light in a way that paint does not, and a smear left by a tired cloth is worse than the dirt it replaced. The rule is straightforward: bodywork shampoo for bodywork, glass cleaner for glass, and a separate, clean microfibre for anything with a lens or a sensor face.

Wax is the other quiet offender. Spray sealants and hot waxes are excellent on panels and a poor idea on sensor faces, where residue collects in the recess and blurs the surface. Keep a little restraint around the badge, the camera pod and the bumper discs — a waxed sensor is a sensor working through a fog.

Winter: the season that blinds the car

From the first gritting run to the last, UK roads coat every horizontal surface in a brine film that dries to a grey haze. Front cameras lose contrast, radar covers crust over, and the dashboard begins offering messages about sensors being blocked or temporarily unavailable. That is usually not a fault; it is dirt.

Rinse before you touch. A pre-wash of snow foam or a thorough low-pressure rinse softens the salt so a mitt lifts it rather than dragging it across the surface. Never wipe a dry or salt-caked lens. Pay particular attention to the rear of the car, where spray from the wheels lands on the reversing camera and the rear plate within a few miles of a treated road.

Spring and summer: pollen, insects and hard light

Pollen arrives as a fine yellow-green dust that settles into every recess and turns to a stubborn paste at the first drop of dew. It also coats camera lenses, which is why lane-keeping systems sometimes behave oddly on a warm May morning. Insects are the radar's problem: a splattered moth on the front cover is a surprisingly effective signal blocker.

Strong summer sun is unforgiving. It reveals smears on the windscreen that no driver notices under cloud, and those smears sit directly in the forward camera's line of sight. Clean the inside of the glass as well — the camera looks through both surfaces.

Autumn: mud, mulch and low contrast

Wet leaves, farm traffic and hedge cuttings all end up on the same bumper-mounted sensors. Combined with a low sun, the road ahead loses contrast exactly when the camera needs it most. Autumn is the season to check sensor faces weekly rather than monthly, and to clear the leaf mulch that gathers behind the rear bumper and around the plate surround.

The number plate is not a cosmetic detail

A plate obscured by winter grime is a legal problem before it is an aesthetic one. Registration marks must be legible, and a plate that cannot be read is something a police officer can address at the roadside and something an MOT tester will inspect. Plates should also be in sound condition: delamination, cracking and discolouration all undermine legibility, and new plates fitted since September 2021 have had to meet the BS AU 145e standard.

Cleaning them is simple, provided you resist two temptations. The first is the abrasive pad, which scratches the acrylic and dulls the reflective backing for good. The second is the hot pressure washer held close to the edges, which can lift the film and force water behind the plate. Shampoo, a soft mitt, a rinse and a microfibre are all that is required. Check the rear plate after every long motorway run in winter.

Products to leave in the cupboard

• Washing-up liquid, which strips protection and leaves a salt-rich residue.
• Ammonia-heavy glass cleaners used carelessly around tinted film and some plastics.
• Any spray wax or sealant applied over sensor faces.
• Abrasive polish on lens covers, plate acrylic or painted parking sensors.
• A pressure washer at close range on seals, camera housings and plate edges.

A ten-minute routine

Rinse the front and rear of the car. Foam or shampoo the sensor areas with a soft mitt. Clean the windscreen patch behind the mirror with glass cleaner and two cloths — one damp, one dry. Wipe each camera lens with a fresh microfibre and a drop of glass cleaner, never a bucket rag. Dry the plate and confirm it reads cleanly from three metres away. Then look at the dashboard: if warnings persist after all that, it is a job for a technician, not a sponge.

Not every driver wants to spend a Saturday on this. A mobile valet can carry out a proper decontamination wash and leave the optical surfaces clear as part of the routine — which, for a car that now does part of the driving itself, is no longer a luxury.