Wire harness plug identification

[kevinr1970]

I thought I had posted this last night but can't find it - was this deleted for some reason?
I'll try again?

Helping a friend put a truck back together. 1986 GMC 4x4 1/2 ton with auto and AC. PO had disconnected the wire harness from the engine almost completely. It was all pulled off to the side.
We were able to find a spot for verything but one plug.

On the main harness that comes down the passenger side valve cover there is an extention that goes out farther than anything else. It goes out almost as far as the grill. This makes me think it should go back over the front of the engine, double back to the back of the engine or go over towards where the blower is mounted. I suppose it could follow the starter wires down behind the alternator too?
The plug is red in color and is at the end of a green wire with a yellow stripe and a light brown/tan wire with a dark brown stripe. The brown/tan might actually be pink but I can't tell. It has two male "plugs" on it that are about 1/8" or less in diameter and side by side.
There are actually three of these plugs that are shaped the same but the other two are black. One of these black plugs went to the smog pump and the other went to a "tower" that is mounted over the passenger valve cover towards the rear, next to and behind the EGR. The fitting had three vaccum hoses too.

I know its hard with no pictures but none are available
BTW, we did start the truck and drive around the yard/house but it is bothering me not knowing where this one goes.
Any help is appreciated!