The turn signal is flashing very rapidly and/or the vehicle’s electronics are reporting a malfunction with my turn signals or lights. This issue can occur particularly in older vehicles or Opel vehicles and is not caused by the bike carrier / the box, but rather by the vehicle’s electronics.
In some vehicles, the problem can be resolved by reading the error code from the vehicle’s computer. In other cases, a Secorüt adapter may help, e.g.:
SecoRüt 50220 LED Lighting Adapter [13-pin socket - 13-pin plug], SECORÜT, A043 | voelkner
To rule out the possibility that the bike carrier / the box light itself is defective, you should connect the carrier to a different car.