Just for future reference. The problem was that the turn
signal/parking light fixture was not making a proper ground to the body o=
the car. I cleaned up the holes in the fender/wing and the securing bolt=
for the fixture and all is now well. Thanks goodness for a
Dremel/Gibbonizer - makes short work of it.
Well done to Bob for guessing corrosion and to Paul for hitting i=
on the head in calling it a classic case of a bad ground. That sure save=
me messing about with switches, flasher units, voltage regulators, etc.