I have a 68 bird and when I put the key in the ignition the horn relay buzzes until I turn the key to the on position, I replaced the ignition switch ,key switch, horn relay. does anyone have suggestions what to try next?

That's a feature. Any of the boys close to you would love to come over and take out for you. lol

Pull the key slowing out of the ignition and it will stop sounding. OR, just close the doors, it should shut off.
If the buzzing does not stop when the doors are closed then the door switches must be the problem.

This made me laugh out loud! Please don't take that wrong and no offense is intended buzzman...and your name is incredibly ironic given the topic which made me chuckle a little more...

So if I'm understanding correctly you replaced a bunch of parts trying to "fix" your perfectly functional key buzzer?

Exactly as Gus points out...if it's actually doing this with your drivers door CLOSED it is indeed not wired or functioning properly...and you will likely need to look to your door jamb switch to fix the wiring correctly to stop the buzzing when door is closed. But if it only does this with drivers door open and key in ignition...this is working exactly the way Pontiac intended.

no offense taken I have owned quite a few old GM cars and trucks that never had this strange option, thanks for the info

I'm not look to hi jack this thread but I was going to post something along the same lines. I have my new wiring in and I love it. The horns work as they should as well as the buzzer. BUT it buzzes even without the key in the ignition with the door open. If the door is closed it does not buzz. Now I'm thinking its the tumbler causing this but I wanted a second opinion before I order a new set.

Seagya - had the same problem after rewiring. My ignition switch was gummed up and thought the key was in it at all times. Removed it, shot it with WD40 several times over a couple of days, and got it cleaned up. Try that before ordering a new switch.

Don't get the WD in the lock mechanism. That's what gummed it up in the first place. Go see a lock smith to get some graphite powder to blow in.

+1 on the graphite powder.

WD40 may clean it out, but new dust and crud will stick to it and clag it up again.