# Parking sensors without drilling the bumper: how they work and what they cannot do _Updated: 8 November 2026_ **Short answer:** Parking sensors without drilling are an aluminium strip stuck on the inside of the bumper, so there are no holes and nothing shows from outside. They beep faster and faster as the car gets closer to an obstacle, but only while the car is moving. > **The service we recommend: Parking sensors** Sensors in the bumper that warn you with sound how close you are to an obstacle. We tell you the price when you tell us the model. [More about the service](https://autoindustrija.rs/en/services/parking-sensors) ## How parking sensors without drilling work A cable connects the thin strip on the inside of the bumper to a small control box in the car. The box creates a weak electromagnetic field around the bumper. That is why these are also called electromagnetic parking sensors. When an obstacle comes closer to the bumper, the field changes and a buzzer in the car starts to beep. The sound of the rear strip changes as you get closer: - **Beeping gets faster.** It starts when the obstacle is about 70 cm from the middle of the bumper. The closer the obstacle, the faster it beeps. - **Fast broken beeping.** The obstacle is 15 to 30 cm away. - **Continuous tone.** The obstacle is 10 to 15 cm away. Stop now. The front strip has 2 sounds. Beeping starts at about 40 to 50 cm from the obstacle and gets faster. The continuous tone comes at 10 to 15 cm. We connect the rear strip to the reversing light, so it switches on by itself as soon as you select reverse. A short sound then tells you the system has checked itself and works. You switch the front strip on yourself, with a button, when you start parking. One short beep means the strip works. If you forget it, it switches off by itself after a short time, so it doesn't beep while you drive. If after pressing the button you hear 2 tones, high then low, 3 times in a row, the strip is not connected properly to the box. Then call us. The bumper comes off for fitting, because the strip goes on the inside. **Whether the strip fits your car: depends on the bumper** - **A plastic or fibreglass bumper:** it fits. - **A metal or carbon bumper:** it doesn't. - **Some pickups, SUVs and vans**, for example with the spare wheel on the tailgate: it doesn't. ## They warn you while the car moves towards an obstacle The strip warns you only while the car moves towards an obstacle. When the car is still and an obstacle is in front of the bumper, the strip reports it only when you start moving towards it. Regular sensors measure the distance to an obstacle, while the strip senses that an obstacle is getting closer. So park slowly and smoothly. In the middle of the bumper the strip warns you earlier, and at the corners later. So approach with a corner of the car more carefully. The strip senses almost any obstacle, of any shape. It senses only glass and ceramics less well. Even with sensors, look around the car before you park. Sensors tell you with sound how close you are, and a reversing camera shows what is behind the car. We also fit it together with sensors. [More about the reversing camera](https://autoindustrija.rs/en/services/reversing-camera) ## What affects the strip and what does not - **Tow bar:** It does not affect it. The strip reports only what is getting closer to it, and the tow bar stays fixed to the car. - **Number plate over the strip:** It does not affect it. The number plate is not connected to the metal of the car, so the field passes through it. - **Metal bar behind the bumper:** It affects the strip only when it is closer than 2 cm to it, because the strip then warns you later. Then we raise the sensitivity. - **Rain and damp:** In the rain the box lowers the sensitivity by itself, so water running down the bumper does not cause beeping. ## How they differ from regular sensors | | Without drilling | Regular | | --- | --- | --- | | Holes in the bumper | None | One for each sensor | | From outside | Not visible | Small circles, painted to match the car | | Rear ones start to warn | At about 70 cm | At 1.5 m or more | | Continuous tone | At 10 to 15 cm | At about 30 cm | | Front and rear | Each bumper has its own kit | 4 front and 4 rear can go on one box | [More about factory and universal sensors](https://autoindustrija.rs/en/advice/parking-sensors-factory-or-universal) ## What the price depends on There is no single price, because every car and bumper needs different work. The price includes the kit, taking the bumper off and refitting it, installation and testing. **The price depends on** - Rear, front or both bumpers. Both need 2 kits, each with its own strip and box. - Sound only, or also a display that shows how close you are to the obstacle. - How much work it takes to remove the bumper on your car. - Whether a reversing camera goes in together with the sensors. ## Frequently asked questions ### Are wireless parking sensors the same as sensors without drilling? No. With wireless sensors, the link between the display and the control box has no cable. Both regular sensors and the strip without drilling can have such a display. ### Are there parking sensors in the number plate holder? There are number plate holders with 2 sensors around the plate. They do not need holes in the bumper either. Unlike them, the strip runs along the bumper, almost from one end to the other. ### Does the strip work on a car with an automatic gearbox? Yes. The rear strip switches on when you select reverse, the same as with a manual gearbox. Have a question about your car? Message us on WhatsApp or call 067 774 1606. ## Read also - [CarPlay for a car without it: activation, a module or a new head unit](https://autoindustrija.rs/en/advice/carplay-on-an-older-car) - [Wireless CarPlay and Android Auto: when it works on your car](https://autoindustrija.rs/en/advice/wireless-carplay-android-auto) - [Android Auto not working or won't connect: what to check](https://autoindustrija.rs/en/advice/android-auto-not-working) --- Page on the website: https://autoindustrija.rs/en/advice/parking-sensors-without-drilling auto-industrija, Belgrade. Phone and WhatsApp: +381677741606. E-mail: kontakt@autoindustrija.rs.