Brake lights

Hi,
I bought this 1947 unfinished Ford. If I turn on the headlights, I have headlights and parking lights. If I step on the brake, I do not have brake lights. (the lights do not get brighter).
Now, If I turn the key on ( leave the headlights off) - step on the brake, I have brake lights. Any suggestions?
Thank you,

Check your fuse box, especially if it uses push on connectors, you might have a wire plugged into the wrong block.

also...
the bulbs may not be good...
that sounds stupid...
but hey...

you also may need dual filament bulbs, but only have single...