My driver's side corner light is having issues. The turn signal filament of the bulb works fine (can signal turns), but the running light filament works only intermittently (it's not burnt out). I tried sanding the contact points, and got the whole bulb working, but an hour later I checked and it had gone off again -which leads me to believe it's temporary function was a coincidence.

Is there another point I might try cleaning?

I've read that the hazard light switch in the shifter console controls the turn signals but does it also control the running corner lights or there a separate relay?