On the red connector, the connections are :
So you have to see very well the tracks, I had a little problem, I think with the first track sold series. Warning ! Attention !
Some tracks haven't the accessories connector in the bottom of the slot.
See two different slots on two different tracks :
So, if you place a wrong track (without bottom connector) between the base and the lap counter (or other accessory like that) the lap counter don't run !
Must see !