Do Volkswagen cars need to add a relay when installing a reverse camera?
3 Answers
Volkswagen cars require a relay when installing a reverse camera, while other car models may not need one. The reason for adding a relay: German cars experience voltage and current instability when starting, with significant output voltage interference. The relay is added to protect the equipment. Function of the relay: The relay uses low power to control high current. Installing a relay allows the signal from the rear camera to be switched to the display when shifting into reverse gear, while also powering the camera. Therefore, a relay with multiple contact points is needed. During installation, only one wire from the reverse gear switch is required to control the relay to achieve this switching.
I've modified two Volkswagen cars before, and whether to add a relay depends on the specific model. For older models like the Lavida and Santana, the original reverse light circuit current is too small, and direct wiring can easily blow a fuse. I once encountered a situation where the camera suddenly went black, and it became stable only after adding a 30-amp relay. But for the new ID series electric vehicles, the body control module directly supports video signals, and the 4S shop technicians said no additional relay is needed. I suggest you first check the vehicle circuit diagram or have the modification shop measure the reverse light current. If the camera power exceeds 500mA, it's better to install a relay. You can buy a waterproof one on Taobao for about twenty yuan.
This depends on the circuit design. I did thorough research when installing one for my son's Volkswagen POLO. Relays mainly address two pain points: first, avoiding overload of the original reverse light circuit, as VW's wiring typically handles only about 1A current; second, reducing video interference - direct parallel connection causes screen flickering. My neighbor didn't install a relay last time, and their wiring harness overheated within six months. I recommend using a 4-pin relay connected to the fuse box's constant power supply, with the reverse light signal as the trigger switch - this powers the camera directly from the battery for maximum safety. While many TikTok tutorials teach using plug-and-play connectors without wire cutting, the proper relay solution remains the most reliable approach.
