Walthers HO F7A rear light function

[woodone]

Hi, I have an Walthers F7A unit that has an Tsunami Sound decoder has a factory install in it.
I want to add two red lights on the front of the loco. Come on when traveling in reverse.
Thought that would be simple- NOT SO! There is no yellow control wire or connection on the board?
There is a socket on the board that is not being used ( marked Bl ) but it is not for a rear light best I can tell.
Any thought has how to get these red lights to come on in reverse?
Maybe a bridge on the motor out puts?
Walthers product # 920-40694.   F7A  #4972

[woodone]

38 reads but no thoughts on how to do this?
Hope someone has some input.

[peteski]

38 reads but no thoughts on how to do this?
Hope someone has some input.

Well, since you are getting antsy, I have no idea.    Besides, it is H0.  But I would imagine that the Tsunamil decoder was in fact designed with more than just front headlight output on it.  You couldn't find any documentation about this decoder online (at Soundtraxx)?

[woodone]

I was never able to find a reverse light function output on the OEM’s board.
The locomotive did not have or use a rear light, so the maker of the decoder (Soundtraxx) made the decoder to the speck the OEM asked for. I would guess it saved some $?
So to get a rear light function I will add a function only decoder to operate the red lights I want.