Occasionally my 1984 R80RT will have a very faint turn signal indicator, and the signals and taillight will blink faintly and rapidly when the turn signal switch is on. Yes, the taillight, too. The cure for this is to disconnect the wire coupler on the left side of the frame (under the seat and above the battery) and simply flush out the connector halves with electrical contact cleaner. The coupler is in a location that is susceptible to dust, probably stirred up by the rear tire. A light brushing with a brass bristle brush has never hurt to shine up the connector. Recently when this happened, I also put a very light smear of dielectric grease on the connector pins. Apply with a Q-tip. After this 5 minute chore everything again worked properly and brightly! Don't run for the electrical diagram and waste money on spare parts before trying this whenever the signals or taillight get finicky!