Why doesn't the Fiesta's reversing radar beep?
3 Answers
Reversing radar malfunction causes it not to beep when reversing. Possible reversing radar malfunctions include: First, check whether the host's power cord is properly connected and if there is current; see if the radar host wire is loose. If neither of these is the issue, the problem may lie with the radar itself. Second, if the problem is confirmed to be with the reversing radar, the first possibility to consider is a damaged buzzer, in which case you need to purchase and install a new buzzer. Additionally, check if the vehicle has undergone any recent modifications. If so, the reversing radar's wiring might have been damaged during the process, requiring the car to be taken back to the original workshop or a 4S store for inspection. Third, check whether the wiring connections at the bumper are intact, verify if the reversing light turns on when shifting into reverse gear, and inspect whether the reversing light's connection switch is damaged. Check if the computer displays any fault codes, and then examine whether the reversing radar itself has any issues. Function of the reversing radar: When reversing, the reversing radar uses ultrasonic principles. The sensor mounted on the rear bumper emits ultrasonic waves that reflect off obstacles, calculating the actual distance between the vehicle and the obstacle, then alerts the driver, making parking or reversing easier and safer. The reversing radar can accurately measure the distance between the rear of the car and the nearest obstacle; when reversing to the limit distance, it emits a rapid warning sound to remind the driver to brake; it can repeatedly issue voice warnings to alert pedestrians.
My Fiesta had the same issue with the parking sensors not beeping a while back, and after some troubleshooting, I finally found the problem. The first thing to check is whether the sensor probes are clogged with mud—mine completely malfunctioned after a car wash because I didn’t rinse them properly. Next, check if the corresponding fuse in the fuse box has blown; it’s usually located in the small compartment under the driver’s seat. If the sensors and wiring are intact but still not working, try holding down the sensor button for ten seconds to reboot the system—some cars just need a restart. If all else fails, it might be a faulty sensor control unit or poor wiring contact, which is best left to a repair shop, as driving without reverse alerts is particularly dangerous. Try to avoid backing into muddy spots when parking, as dried mud can easily block the sensors.
Car repair shops often encounter Ford Fiestas with non-functioning reversing radars, typically due to several common reasons: the sensors being covered by mud, snow, or car covers—simply cleaning them off should help; blown fuses, especially in cars with aftermarket electrical installations in the trunk; loose wiring connectors that may disconnect on bumpy roads; a damp or water-damaged radar control box causing failure; and an easily overlooked issue—accidentally pressing the radar mute button inside the car. It's recommended to first check for dirty sensors and mute settings yourself. If that doesn't work, inspect the 15A fuse labeled RADAR in the fuse box. Newer models also allow adjusting radar sensitivity via the central control screen, so remember to check the settings interface.
