Quoted from Skidave:
If all the lights are out behind the backglass, it is either dirty / mis-adjusted contacts on the Lock relay OR the plugs that connect to the back box (called Jones plugs) need to be cleaned and reconnected. Remove power, remove plug assemblies, clean carefully with a scotch brite pad, wipe with isopropyl alcohol and reassemble. I also clean the sockets.
The 100K light is a separate issue, but I would not tackle it until you get all the lights working.
Your schematic has been dissected here with great explanation by memeber @Xsyvtoys. Do a search and it will step you through everything.
...or the fuse blew. check the fuse for the back box.