Hi, Anonymous for this scenario you will need your service manual that has all fastener torque specs -fluid capacities and a wiring diagram on the back pages, parts fiche, and owners manual if you can not find the best tool you ever bought for your Honda, despair not, for a mere zero $0 you can download another one.
For more information about your issue and valuable "FREE" downloads that you will need for viewing or printing please click on the blue links below. Good luck and have a wonderful day.
https://www.goldwingfacts.com/threads/left-hand-controls-replacement.669697/
https://www.goldwingowners.com/threads/06-gl1800-right-handlebar-switch-assembly-replacement.126485/
https://www.manualslib.com/manual/1142922/Honda-Gl1800.html
https://www.partsfish.com/page/oem-parts-for-honda
https://www.manualslib.com/manual/805153/Honda-Goldwing-Gl1800.html