What's the reason for no video signal in the rearview camera?
4 Answers
Rearview camera connection data cable is loose or poorly connected; rearview camera is damaged. Below is an introduction to the rearview camera system: Applicability of the rearview camera: When the driver is reversing, the rearview camera system displays the situation behind the vehicle on the screen to assist the driver in operation. The rearview camera is generally used to display distances during reversing and parking, allowing the driver to clearly understand the environment behind the vehicle from inside the cabin, avoiding injuries or damage to objects while reversing. Application scope of the rearview camera: After years of development, the rearview camera system has upgraded its technology, improved performance, and been applied to various vehicle models, such as sedans, buses, coaches, school buses, and passenger vehicles. Whether in terms of structure and appearance or performance and price, current products each have their own characteristics. The most commonly used types are digital display, screen display, and multifunctional rearview mirror display.
I've encountered this reverse camera black screen issue before. Last time after rain, the rear camera was covered in mud spots and caused the same problem. First, try cleaning the tailgate camera, then check if the wiring connector in the trunk is loose - those connections often get jostled and may cause poor contact. Another possibility is the infotainment system freezing; try turning off the engine and waiting five minutes before restarting, just like rebooting a phone. If you've modified the center display navigation system, there might be protocol incompatibility between the head unit and camera - my friend's car had constant screen flickering after installing an aftermarket navigation system. The most troublesome case is rodent damage to wiring - last winter mice chewed through my car's GPS antenna cable.
No signal from the reverse camera is most likely a wiring issue. My old off-roader had this problem due to aged wiring: the wires at the trunk hinge were repeatedly bent, breaking seven metal strands. Peeling back the rubber sleeve revealed green oxidation marks, and the multimeter showed only 0.2 volts. I recommend first checking if the camera's power supply line has 12 volts, then testing if the video cable's impedance is around 60 ohms. Loose RCA connectors behind the head unit are also common—once, water splashed in during car washing and caused a short circuit. Of course, it's also possible the camera chip was damaged by direct sunlight, especially with black plastic casings that absorb heat easily.
Last week, while repairing a customer's car, I encountered this exact issue. The reverse lights were on, but the display screen remained black. After inspection, it turned out the video converter box had water damage—this component is often submerged in the spare tire well. During testing, you can shift into reverse and listen for the switching sound from the head unit; if there's sound, it means the signal has reached the main unit. Also, pay attention to the impedance of aftermarket cameras—using a 50-ohm replacement for the factory-standard 75-ohm can cause screen distortion. In an emergency, try slapping the trunk lid a few times; sometimes the vibration can temporarily reconnect loose contacts. If the camera is powered from the reverse light circuit, trying a different bulb can provide a more straightforward test.
