Check socket for corrosion-and make sure it is grounded
change the fuse if not replace flasher
If the center one works then it will almost certainly be 2 Blown globes.
blown fuse or turn switch bad
The only thing common to all those lights (but not to the center brake light) is the hazard switch. I'd check that next. On my 96 Century the hazards override the signals and brake lights meaning that the signals and brake lights must be wired into the hazard switch somehow.
There are several stores where they sell window lights, some of them include Gaebler, you can also purchase some window lights on the internet. Another store that sells window lights is Everest, they can also be found on the internet.
get a new window switch
Yes. I have found the schematic in the back of most "Haynes" manuals.
The '67 has Front Turn Signals under the headlights, under the grill. The '67 has little front triangle windows for a two-part driver and passenger side window. The '67 has no rear side marker lights. The '67 has a light colored grill shroud, a bit grey. The '68 has Front Corner Turn Signals that run around front to side. The '68 has a one piece side window (no triangle openers). The '68 has rear side marker lights fashioned in the likeness of a Pontiac symbol. The '68 has a dark colored grill shroud, black. I know of no other significant body style differences. The wing window is the most obvious and is the easiest giveaway to indicate a 1967 Firebird.
lights
You have to get on the bed. there will be a book with morse code. use that to read the signals.
File on the top left corner, and open new window.
Theres this plate at the bottom of your steering colomb, inside it actually, that has the contacts that work all the signals/ brakelights and the like. It apparently wears out after a while. if you fiddle with the turn signal the brake lights will work.you have to take the steeringwheel off and replace the sucker to really fix it. Just watch your tail lights in a store window to see what i mean, shake the turn signal thingy and your lights will work.