Hello all, I'm new to the forums and was hoping to get some answers related to DCC as I've recently added it to my layout and now the temperature has dropped and my controller doesn't seem to interact with the locos.
I'm able to run them in analog however (I tested this using a separate controller)

For reference I use a Bachmann EZ command controller and Digitrax DZ123 decoders

What could be my issue? I appreciate any advice or help in advance

You mean it got colder and the EZ command ceased to function?

Where is your layout located that temperature would be a factor?

I have a new Bachmann RS3 engine DCC ONBOARD But it will not program to factory set code of 3 but will program to the cab number of 8601 but only the light function  will work , no horn sound, no bell sound.
I am using an NCE DCC system.If I try and program the engine to factory set code of 3 , nothing happens, it will not run, but set to cab number 8601, it will move forward and reverse and the headlight turns on and off with the headlight button on my NCE controller.
I have used "Program on track using  the CV numbers and values for the horn and bell but nothing works. The engine does run forward and reverse programmed to the cab number and the headlight can be turned on and off, also direction button works but  no horn or bell sound.
Trying the CV numbers and values for he horn and bell also doesn't work.

Does anyone have any suggestions or recommendations?
I have no idea what decoder is in the RS3 as I have not taken the shell off of it.

Some ON BOARD decoders are finiky and you have to put a 1/4 or 1/2 watt 1,000 ohm resister across the track when programing. Similar to what's you have to do with some sound decoders. Also, SoundValue locos have sound, not DCC ONNBOARD locos.

Len

 To me this sounds like a preowned locomotive with an unknown aftermarket decoder. Correct me if I'm wrong.

But if by some miracle it happens to be a Soundtraxx product, follow their instructions to reset the decoder to factory default by doing a cv8 reset to value eight.  You then break the power to the locomotive by rocking it completely off of one rail, then setting it back down and you should see the headlight blink 16 times if the reset is correctly negotiated.  At that point, the address will be 3 and all functions should work.

Have you tried putting this engine on an actual program track?  If you do that, you can read the address and you can read what each CV value actually is.  One of the first things that will do is provide you a manufacturer ID number which is established by NMRA standards, and you can look it up and see who actually made this decoder.  Then you should be able to get a CV list and know which CV actually does what.

As Len has stated DCC Onboard are non sound decoders. What you describe is the decoder doing what it is supposed to do.