Yes, more details please. If the light is blinking off at times, it's probably just dirty track/wheels/pickups. If it's making some sort of pulsating pattern, it could be that ti got programmed for a special effect. A steady blink when it gets set on the track and not being able to move the loco is a short indication on the motor side for some Digitrax 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.
What scale, make and model is the locomotive? Is the decoder factory installed? If not, can you ask the installer what programming, if any, was done? Is the decoder programmed for a lighting effect simulating a flashing beacon or mars light?
I know, questions, not answers. Good luck.
I am running a digi trax zephyr unit 1 diesel unit light pulsates is the decoder shot