24V to 6V conversion?

I've got a NOS conversion box for a trailer. The directions are dated 53 and mention the M21 ammo trailer. This is a box that is bolted and hardwired to the trailer and has an M series pigtail to hook up to a truck. Worth anything or should I keep the cable and scrap the rest?

Don't pitch it. If you can remove the cable without ruining the box, good.. but anything original like that could be useful, depending how it does the conversion. If nothing else, someone might appreciate the electronic parts inside. Can you open it and show the guts in a picture or two?

I'll try Patrick. It's got 4 resistors in it, I know that!