Hi all,

I just purchased a 98 Ti and the brake lights are on when I turn on the headlights. Also when I step on the brakes, the driver's side turn signal lights up. This happens with the headlights off.

you definitely have a wiring issue. Any fuses blowing, too?
You should post a picture showing the actual bulbs getting power when the light are on, brakes on, etc. It will make it easier to help you out.

Wrong bulbs or crappy bulbs.

Wrong bulbs or crappy bulbs.

Yup, bought some new bulbs and everything works.

Some dual filament bulbs end up shorting out.
I think the contacts are too close together.