I recently swapped out my handlebars to include extending electrical lines and internally wiring. After putting it all back together, the left turn signals front and rear don't work, headlight doesn't work, and running light on brake doesn't work. Is there a common connection to all these that may need checking or do I need to pull the main harness out of the backbone again and check everything? Also, according to my repair manual there is only 1 fuse for all the lights, is this correct?

 

There is only 1 fuse for your lights, that is correct. It controls your headlight, both of your front running lights, and your tail light. It does not control your blinkers or brake lights. That is controlled by the #4 accessory fuse. Since you have a manual, I'd start by actually writing down the entire circuit. This will tell you if it has a common ground or component that should be checked.

Hope this helps.