It does vary somewhat from decoder to decoder. By default most decoders give a directional headlight that can be turned on and off with F0 - are yours not coming on at all? If so, you may hev the LEDs wired backwards. Don't worry, you didn't break anything, as long as you had the 1K resistor in the circuit as well. The blue wire from the decoder, while common for all functions, is the positive lead. LEDs do care about polarity.
One thing that can help greatly is JMRI and specifically the DecoderPro part of it. You don;t have to actually buy the interface for your system, you can use it with a simulated layout connection and use the programmign menues to select the settings you want. There is a page in the pgorammer labeled 'CVs' which will show the values for all CVs in the decoder based on the settings you have made. The ones hilighted in orange are the ones that have changed from the defaults. Program those using your throttle. Eventually you;ll probably want to get the NCE USB interface to connect to your system, then DecoderPro does all the programming of your decoders.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
Yes, NCE decoders use different CVs for lighting effects than Digitrax decoders. You need to refer to the decoder documentation for each type you have to know what CV values to set.
I believe most Digitrax decoders use CVs 49 and 50 for lighting effects, whereas NCE uses CVs 120, 121, and 122.
But if your lights don't work at all on the decoder default values when you press the "HEADLIGHT" button on the PowerCab, then you probably have the LEDs wired backwards. The blue decoder wire is the POSITIVE lead and the white and yellow decoder wires are the NEGATIVE. The 1K Ohm resistor can be in either the blue or white/yellow, but you must have a separate resistor for each LED.