The schematic beneath is a new project of me.
The theory behind this is: My car has a very fool proof bulb failure detection and warning system. CANbus proof LED bulbs can't fool the car and just a parallel resistor will make a faulty LED bulb undetectable. So when the parallel resistor (wich imitates as a incandescent bulb) can be "switched" off when a short or open circuit LED bulb is "detected", the car will see a faulty bulb.
But... another common fault in LED bulbs is that the LEDs are burned, but without a full open or short circuit. They just take less current/voltage when this happens. So there should be a third "detection": the voltage/current drop. How can I managa that, without heavily increasing the number of parts and most important, the costs.
At this moment, it is only for the rear brake and indicator bulbs and every bulb needs a circuit as the example below, with 2 circuits combined in 1 box and 1 box for each side.
Thanks in advance.
Figure 2 by @Transistor. A more conventional drawing with voltage decreasing from to to bottom, chassis symbol used for the vehicle groun and ground symbols all pointing down (towards the ground).