I don't know if it has changed on the newer models but for the 96-99 MY Subaru's when the parking lights are on and the turn signal on how did the lights flash?

was it:

Dim, bright, dim bright?

or on, off, on off with the On being full brightness?

Also I take it that it's a 12V input to the bulbs correct?

All lights should have 12 volts going to them except the dash lights when they are dimmed and some of the warning lights at certain times.

The turn signal indicator in the dash should turn on and off I believe. If there is trouble with the indicator circuit or bulbs the dash light will be steady ON when the trouble side is turned on.

he's talking about the actual turn signal/parking light bulb. it should be dim bright dim bright because the 5w filament doesn't turn off.