On sets with green wiring, there will be fuse bulbs that have a white lamp base. On sets with white wiring, there will be fuse bulbs that have a green lamp base. Carefully pull the fuse bulb from the lamp holder and replace with a fuse bulb from your spare bulbs package included with each set.
Check the fuses in the male end of the plug (the end with blades)
Make sure the lights are not plugged in. Locate the fuse holder in the male end of the plug (the end with blades). Carefully open the fuse holder by sliding in the direction of the arrow. Carefully pry the fuses out by the metal ends only with some tweezers or eyeglass screwdrivers. Replace both fuses with new ones and close the fuse holder cover. Plug in lights.
I've done troubleshooting, have identified the problem, and need replacement accessories.