I removed the fuel cooler to replace it's O rings in my Td5 D2 today and all went well until whilst re installing it I found a green 2 pin plug ( the same size as the black plug that goes on the vaccuum tree with the 3 hoses coming from it ) that I can't remember removing but it looks too clean on the inside and dirty on the outside for it to be an unused plug. Where should this plug go.
And yes, I am a bit embarrassed.

Thanks,
Anthony.