i wish it had been that easy....but it actually wasnt too hard. i opened up the light bodies, there are circuit bords in there for the night time military running lights....throw them away. now the 24volt bulbs, hang onto them so you can take them to the parts store and match the twist lock pins on them for the same but on 12volt bulbs. comming out the back on my light bodies there are 4 wires, i just used 2. the light body is the ground, so just test the wires for which one goes to the centre pin on each of the bulb mounts. these are the only 2 you need, one for brake/signal, one for running lights. the other 2 that were the night time military stuff i just cut off. go get your 12 volt bulbs that fit, hook up the 2 wires that you need and voila...12 volt trailer lights. i am not at home or i would get some pics for ya. hope this help anyway.
oh yeah i removed the whole wiring harness from the trailer and ran all new wires and did the connections right at the back of the light bodies just so everything was new and i could then use a 4 pin regular trailer connector.