P2K 0-8-0 headlite ? (plea for help)

[MrMunchkin]

I recently put a decoder into a P2K 0-8-0. everything works fine EXCEPT for the front headlight (yes I did change both the front and rear bulbs over to leds) the rear one works fine but not the front one (yes, I've tried a couple different leds on the chance that the first one was defective, with no luck) this is a plugin decoder, so there's not much chance that it's wired wrong (I've tried a couple different decoders, each one works the same in this loco and works fine in others). Anyone have any ideas what's wrong? THIS IS DRIVING ME NUTS. Thanks in advance.  P.M.

[SteamGene]

You realize, I hope, that in steam times, up until the very end, locomotives turned the light on at night. 
Gene

[Nigel]

Please confirm that you installed current limiting resistors for the LEDs, and you scoped the whole circuit for shorts and open with your multimeter.

[Virginian]

Reverse the polarity just on the off chance.

[MrMunchkin]

Nigel, no  did not, and I will this afternoon. I didn't think that was the problem since the rear light works fine without one, but it could be. Thanks.  P.M.

[Hoople]

Make sure the light is getting power- sometimes the wire contacts don't hold that well. My 4-8-2 has the same problem but I know I screwed up on re soldering plugs...