speedo sender? how does it work

[new2this]

my speedo is broken as it doesnt read anything.

i have removed the sender from the gear box and had a look how it works, i can see the shaft is driven by a cog but at the top of the sender where the cap clicks on and the plug clips to it, i cant see how the signal goes from the spinning shaft to the top of the cap where there is a metal contact.

it may be broken as when i went to investigate the cap was not on the sender so some parts may be missing. any suggestions as to what it should look like in there? any part numbers or prices floating about for a new sender for a mk3 cupra

 

[goble]

it creates a voltage by spinning, and is probably just this that has gone

 

[new2this]

how does the voltage from the spinning shaft travel to the cap? does anyone have a etka diagram of one or a breakdown of the assembly