Not able to turn off headlights while key is turned in ignition?

Sounds like your car has the Daytime Running Lights option. That turns on the headlights at half output when the engine is running in the situations you mention. On most vehicles of that vintage if you apply the parking brake on to the point the light on the dash tells you the brake is set comes on, the DRLs will shut off. What I generally do if you don't normally use the parking brake is to access the switch and add a bypass switch if the factory didn't provide one. In your case the switch is mounted above the pedal in the drivers footwell. When you step on the pedal it allows the plunger to extend and that connects the signal pin to ground. So, a simple on-off switch that connects the light green wire to the black ground wire would do the same thing. If you do use the parking brake, then just set it those few clicks and see if the light goes out. What I normally worry about is that it hasn't been used and could cause the parking brake to apply and then stick on just a bit. That is when I add the switch or if the plug isn't hard to get to a short jumper wire would do the same thing as a test.