Stroseph, welcome to the HDTimeline forum and your first diagnostic thread. When you say turnsignals work intermittant at best...does that mean left or right work the same...and do the lights stay on, stay off or don't flash at the correct rate? When did the intermittant failure begin...after a rain, recent service and what have you done so far?
Typically, the most common cause would be corrosion in one or more of the light socket/terminal connections, usually due to condensation or water intrusion (I looked at a Harley parked next to mine awhile back and could see water halfway up the left rear signal...! Next thing would be insulation cut or pinched, usually where the wire passes thru a housing or metal holddown clamp or where bending/flexing occurs.