Tail Lights won't turn on when I turn on headlights

[MomoRed]

I've got a problem with turning on my rear tail lights. I've got a 2004 WRX Wagon.

When I turn on my headlights, my tail lights should turn on but they don't. They do however come on when I brake. I've replaced the fuses and the bulbs and all looks fine. Both the right and the left tail light respond the same (they only turn on when I brake). Any ideas?

Thanks

[vttk_mig69]

relay or ground would be my next guess.

[EvoEatr]

check the virgin switch on top of the steering column ive seen these get caught in the middle position (between on and off) before and cause some odd issues...