Tether Connector suggestions

First off, the coupler, lamp, smoke, and AC common are, well common.  You just need one wire each for coupler, lamp, and smoke.  The returns for all of those items are the frame ground which you happen to have handy since the pickups are in the locomotive.  Personally, I use the MTH 10-pin tether, and I double up the wires for the smoke unit as I have extra wires.  The MTH tether has four #22 wires and six #26 or #28 wires, hard to determine which.  The heavier wires are used for the track power and motor, and then I just allocate the rest of them to the other functions.

OK, I had been thinking of going that way.  Tieing the common side in the engine on the coupler/light/smoke.  The directions say to do that for smoke as I showed in the pin out.  I was being reluctant worrying that the ground might matter in some magical electrical way.  I am mechanical by trade, lots of experiance packaging electrical things.  I have had bad ground experiences, unrelated to this of course, but I was just being VERY careful.

Do you buy the connector set from MTH directly?

Would you by chance know the part numbers off hand?  I don't have any MHT experience so if you could point me that would be great.

Thank you 

I use the AG-0000039 PCB in the locomotive and carve out a spot for it if it doesn't exist.  I use the BC-1000002 universal tender harness for the tender side.  I buy directly from MTH.

Ground does matter in some magical way, it must be ground!

I mean no disrespect to electrical guys.  I just always felt that as soon as I would get something figured out we would run into something that did not fit.  A lot of what I do is RF so that just adds to the confusion.

I will check the parts out to be sure I understand.

Thanks alot

Looks good I ordered a couple of sets to get my Mark1's on it.

Thank you for your help.

ERR specifically has the front and rear lights returning to pin 6 on the Cruise Commander, while the smoke unit goes to ground. ditto with the couplers. Any reason why they don't have pin 6 just go to ground and one side of each coupler going to ground?

The smoke and couplers draw quite a bit of current, I suspect it's just a precaution to avoid excessive current in the PCB ground trace.