How to program a function decoder for backup light?

[nickelplate759]

I'm putting DCC in a Concor/China 4-6-4.  It occurs to me that if I put a normal mobile decoder in the boiler (like a TCS M1 or Digitrax DZ126 for example), the only thing I'd need to run more wires to the tender for is the backup light.   If I use a function decoder for that (like a Digitrax TL1), then I don't need any extra wires!         My question is - how do I program the two decoders to work together as if they were one?  Also, does it matter if they are both from the same manufacturer?

George

[tehachapifan]

I'm relatively new to DCC and have been pondering similar setups. Others will be able to answer much better, but I believe one option might be to program them as a consist. I have a DCC switcher and a caboose with a sound decoder that I routinely couple as a consist, but they aren't wired together for pickup purposes like your tender is(?). I think you might also be able to simply give them the same loco address. I believe the light would need to be programmed to function when the loco reverses (FOR) or on its own separate function command that is not programmed in the other board. I believe the HO folks routinely put more than one decoder in the same locos, so it's definitely doable. However, wait to hear from someone who knows for sure!

Edit: Realizing my reply had almost no value whatsoever, I did find what appears to be a helpful link on the subject and sent it via PM. I would post it here but can't remember or find the forum rules on posting links.

[jagged ben]

Just program them to the same address.

As for the practicalities of programming....  I don't know if it's easy to separate the tender from the loco on this model. 
If it is easy, then just separate them and put one at a time on the programming track.
If it's not easy, I suggest using this method posted by Ken Rice in another thread.

And btw, there is no problem with linking to content on other websites in this forum.

[nickelplate759]

it's easy to separate them.  Sounds like an easy solution overall!

[mmyers]

Yep. Program the function decoder to the same address as the loco decoder. If you only want the light to be on in reverse,use the yellow wire. For all the time illumination, connect yellow and together and to the lamp, led, etc. You may have to place a load on the program track. The engine will suffice for that.

Martin Myers

[peteski]

I have several MU-type trains (European and Japanese).  When one end is powered and the other is a dummy, I install a conventional decoder in the powered unit (with just the forward headlight wired - white wire).  Then in the other, dummy end unit I install a function-only decoder and wire up just the "rear" headlight (yellow wire). If these trains also have red EOT lights then I wire the headlight to one function output, and the EOT markers to the 2nd function output on each decoder.

I have some MU-trains where the powered unit is in the middle of the train (both ends are dummies). In those cases I use 3 decoders" one just for the motor on the powered unit and 2 function-only decoders for the headlights (EOT lights) in the end units.

I like to use the same brand of decoder for all the decoders in the train.  I also program them all for the same address.