Quick question for ellipsoid (US) headlight upgrade ~ Spare wire?

[The Driver]

For the guys that know the US ellipsoids are supposed to be plug and play basically, how ever there is a third wire on each the high an low. Is this ground if so Can I just bolt it down/ground it?

Thanks

[EA8]

if you measure voltages across then, the extra wire on the lowbeam should only read a voltage when you highs are on, so I would just cap it off. For the highs, just run both of them in for power. Usually, the ground wires are brown, but the best way to find out is take a digital multi meter and explore.

Cheers