where does this plug go

[89bmw325ikid]

ok i took out my cluster to see if there was water behind the dash(thank god there wasnt) and forgot where this plug goes. it is a 1 pin plug with a blue/yellow wire to it. it goes somewhere in the group of green on the bottom of the speedo but idk which spot. thanks in advance...

[AdamF 88iS]

Any one it will fit into. There are 2 or 3 of the slots it fits with and they all send the same output signal.