[Hutch]

First thing to do is check to see if you have a wiring harness and bulb sockets as the earlier trucks just used the reflectors with no wiring for lights.
If you do indeed have the wiring then check for voltage.
Bad connection or blown fuse maybe a disconnected wire.
When folks try and wire these trucks up for trailer lights they tend to hack up the wiring.
This would be a good place to start also.

Have Fun