Lionel 785 Hudson Wiring

It goes to the top left of the E unit next to the blue wire.

Still need help with this; the blue wire heads down to the bottom of the E-unit, so I'm still a bit confused. Here's a better picture, with the locomotive facing to the right.

I have never worked on a 785, but it looks like typical post war wiring.  The wires to the e unit drum should be a black wire from center rail power, the center contact to wires, which should be yellow and blue and go to the brush holders.  These are the wires that get reversed to change direction.  The last wire from the other outside finger is a green wire that goes one of the motor field connections. The other field wire is probably grounded to  the motor frame. The two black wires going into the loom are a center rail power wire that goes to one of the terminals that turns the eunit on and off. The other black wire is power back to e unit coil from these terminals. The loose wire appears to be either the power to the eunit plug or power back to the eunit coil wire.  If it is power to the e unit plug, typical this comes from a terminal with several wires connected to it, including power from the center roller, wire to the eunit drum, wire to lights, and wire to smoke unit. This is the terminal that I would look for to see if this is were your wire is missing from.  

Alright, hopefully this is it. So I did solder that wire a while ago, but now it can only go in reverse and neutral. Here's another view of the E-unit, and this picture should show how it is wired. Did I put that black wire in the wrong place?

Yes,  The black and green wires go to the outside contacts, the blue and yellow wires go to the inside contacts. The black wire to power, the green wire yo the field, and the yellow and blue wires to the brushes. It sounds to me like one of the inner fingers is not making contact in one position. Since it goes one way and not the other, probably a problem with the drum.  Maybe corrosion or dirt on one of the drum segments.

@David Johnston posted:

Yes,  The black and green wires go to the outside contacts, the blue and yellow wires go to the inside contacts. The black wire to power, the green wire yo the field, and the yellow and blue wires to the brushes. It sounds to me like one of the inner fingers is not making contact in one position. Since it goes one way and not the other, probably a problem with the drum.  Maybe corrosion or dirt on one of the drum segments.

Ok, so you're saying according to the picture the blue wire is in the wrong spot?

I am sorry, I did not see the second black wire. On the four finger contact board the center two contacts are connected together, made as one piece. On the two finger board the two fingers are connected together, made as one piece. The yellow wire and blue wire are fine.  Each is connected to one pair of inner fingers. And the yellow and blue wire, on a single motor loco are completely interchangeable. Each wire connects to one brush holder, does not matter which one.

What I missed was the second black wire on the two contact board. That should not be there. On the two contact board there should be only one wire, either the yellow or blue wire. On earlier eunit, there was just two yellow wires, no blue wire. One yellow wire was changed to a blue wire when Lionel went two motor locos (2333).  In rare cases that second black wire might be there to reverse the head lights. But that is really rare.

@David Johnston posted:

I am sorry, I did not see the second black wire. On the four finger contact board the center two contacts are connected together, made as one piece. On the two finger board the two fingers are connected together, made as one piece. The yellow wire and blue wire are fine.  Each is connected to one pair of inner fingers. And the yellow and blue wire, on a single motor loco are completely interchangeable. Each wire connects to one brush holder, does not matter which one.

What I missed was the second black wire on the two contact board. That should not be there. On the two contact board there should be only one wire, either the yellow or blue wire. On earlier eunit, there was just two yellow wires, no blue wire. One yellow wire was changed to a blue wire when Lionel went two motor locos (2333).  In rare cases that second black wire might be there to reverse the head lights. But that is really rare.

No worries, thank you very much! And yeah, I don't think I properly clarified it myself, but the black wire on the two-finger board was the one that originally fell off, and I think I only put it in the spot next to the blue wire because I thought I saw solder in the empty hole, making me think that's where the wire previously was. I also went back to your original response, and I think I realize what terminal you are talking about.

I'm sorry I keep asking about this, but is this where the wire is supposed to go?