My speedometer is not working at all… Since the wiring, gearbox and speedometer are from different cars I don’t know where to start fault tracing. I think the wiring is right with + connected to +
and the two cables from the transmitter connected to the two bottom connectors (the one in the bottom also have earth to it).
Is there some why that I can test the speedometer? And the same for the transmitter in the gearbox?