CANBUS ? Camera works on bench but not when installed.

Normally, a backup camera is powered by the same power line as the backup lights and powered to provide video when a gear is put in reverse and backup lights come on. 12VDC is a normal power requirement for backup cameras.

Modern automobiles have many electronic control units (ECUs) and a Controller Area Network (CAN bus) provides the communication backbone between ECUs.
In some vehicles, an ECU regulates the backup light voltage to less than 12VDC. This causes a problem for the backup cameras that use the backup light positive as their power source. 12VDC is required for the backup camera but less than 12VDC is provided.

The result is No VIDEO.

In such a case, we will have to utilize ACC+ and use a relay to provide power to a backup camera when the gear is in reverse.

Powering camera using a relay:




  1. Camera power positive (PIN 30) --- Red on camera wire
  2. Reverse light positive (PIN 86) --- Consult car manual/dealer for cable color
  3. Ground the relay (PIN 85) -- The negative battery pole  or chassis
  4. Connect 12V power source (PIN 87) -- ACC+ (e.g. 12V cig. ligher socket/charger socket or radio power source)

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