drivers front turn, driving light not working

Drivers side front turn signal, driving light doesn't work. Passenger side turn signal, driving light works fine. The wiring harness seems to be in good condition. I have already changed bulbs, checked for power at socket which there was no power at the time, changed turn signal assembly in column. Some times not very often it will work if I leave the bulb in. The turn signal bulb is also the driving light bulb in this car.