Alternator wiring

[jakobgr]

So due to starting issues I ventured on replacing my starter...which is an adventure which required to me to disconnect alternator. Now I am on my way putting things together and I've seem to have mislaced a wire....i.e. there are 3 connectors on the alternator and I cant find the 3rd missing wire. Pretty sure there was one since I have the nut. Anyway, I've posted a picture with a killer home made arrow pointing to the missing wire location.
So anyone able to guide me and give me a hint where that wire is routed from(is it just a ground maybe that I can take from somewhere else?)

[xxxJohnBoyxxx]

Mine only has 2 wire going to it under the protective cap. If the arrow is pointing to what I think it is that holds the black plactic on the back of the alt and nothing connects there.

I could be wrong but I have nothing connected on mine and I never have

[familytruckster]

Same here, just the two wires under the rubber boot.

Thats a bolt that holds the guts of the alt together ( I went and checked spare alt I had sitting around)

[jakobgr]

Well thanks guys....I may possibly just have taken the nut out w/ou looking too well(I've been known to work fast)