Tender-Loco witing harness for Soundvalue 2-8-0?

[DaveGard]

I am in the planning stages of swapping the tender on my Soundvalue 2-8-0 for a vandy tender I purchased on eBay. This will require installing a decoder (probably a Tsunami 1100-2) and speaker in the new tender, and then running motor power (2 wires) and headlight power (2 wires) from the decoder in the tender to the loco.

Can anyone tell me what the 5th wire between the stock tender and loco corresponds to? There are five wires... I would guess that two are from the decoder to the motor, and two are from the decoder to the headlight. But what is the 5th wire? Ground?
Thanks,
Dave

[Mike C]

 Previous tenders have always had the board at the plug marked . Look at the board ans see if you see M+ M- L and R markings , I think the other wire will be the light + wire ......Mike

[DaveGard]

Thanks for your reply... I assumed that the track L and track R power was carried from the chassis to the tender entirely by the drawbar contact wires (which connect the two sides of the chassis to the pickups on the first tender truck). There are five insulated wires in the harness in addition...

I will open it up and look at some point... just trying to put that off as long as possible. I am just in the planning and acquisition phase of my tender replacement project, and likely won't actually start until after the holidays. Fitting the decoder and speaker into such a small space is going to be a challenge...