Just noticed that my taillights are out. Blinkers work, but no brake lights or taillights. 20A fuse was blown, I replaced it, and it blew as soon as I stepped on the brake pedal. Any common place to start checking? Somewhere way back when, somebody wired in an alarm system on my 67 400; undoubtedly, this will complicate things.
Thanks in advance--
Tom

Since you have to pull the driver's side kick panel to disconnect the tail lamp harness, start with a visual inspection of the trunk harness wiring. Then remove all four taillight bulbs and disconnect the pigtail for the license plate lamp and try again. If it no longer blows the fuse, you have a shorted or incorrect bulb.

Do the taillights and parking lights work if you don't step on the brake pedal? Do the hazards work in the back if you don't step on the brake pedal? If so, the brake pedal switch itself may be bad.

I'm assuming the 20A "DIR. SIG./BACKUP" fuse is the one that blows?

If the turn signals work then I would think the problem is between the fuse and the turn signal switch. That's where the brake light and turn signal functions are shared in the circuit.

Do what Vikki suggested to further isolate the problem.

Thank you both. To be specific:
the blinkers and hazard lights work and blink both sets of brake lights. When I turn the lights on, or step on the brakes, no taillights.

It is a 20A fuse, the one at the bottom of the fusebox, but it's not tail/blinkers. Just tail lights.

I'll try removing all bulbs and see what happens. I'll also inspect the wires for fraying, etc.

Thanks!

Tom