OK "turn signal lights stay on" isn't clear. Which lights? anyway... when the turn indicators in the dash come on with the park lamps there is a loss of chassis ground at front park/turn fixtures. Park lamp current finds a ground through the turn circuit instead of through the bulbs base and fixture. Rear lamps can't back feed in this manner since the path is interrupted at turn signal switch for brake lamp operation.
So if the turn indicators in the dash are the issue, check ground wire connections at radiator support.
