[48 IDA]

Jeff, The first thing to do is check all your grounds for the lights.
There is a black box, (at least on mine) mounted under the dash that
controls the current to the turn signals lights. It is designed to work
the turn signal, and brake light on a single circuit. If all the lights
come on and only one flashes, I would suspect this signal flasher box.
Check for power going into the box, and if you only have one circuit
working coming out of the box. I would replace it. I believe that you
are able to pick one up from a towing supply outlet. U Haul. It will
be a flasher control for a single circuit brake and turn signal bulb system.
This unit allows the bulb to flash while your foot is on the brake pedal
indicating the way you wish to turn.
There are two flasher control units. One works with a single bulb brake
light and turn singal. The other with seperate brake light bulb, and turn
signal bulbs. Just wire in the box per directions, and you will be ready
to go.

Good luck

Don