anyone know what the relay in the right rear  (passenger side) 3 lid compartment on a 69? looked at manuals and wiring schematics and doesnt show it. Possibly horn? mine not working. Thanks

That would be the alarm relay. You should also see what looks like a turn signal flasher back there...cause that's what it is...a turn signal flasher! Your car apparently had the optional anti-theft alarm. The arm/disarm switch is on the rear panel, between the tail-lights, and the alarm horn is on the driver side, rear, above the muffler(if it's all still there, anyway).

That must be what it is. I was wondering what the other horn was for. Now to try and find switch. Thanks

The switch is easy, its the key slot between the tail lights. A guy once asked me if that was the way to open the trunk.

A lot of the switches have been removed, and the holes 'glassed over. That was the way they "fixed" rear body damage...rather than do it correctly. If your car doesn't have the switch in the rear panel, look closely at different angles, and you might be able to see where it used to be.
The alarm was an option, so not all cars had them, but...if you have the relay in the storage compartment, it was a factory installed alarm.

You'd be surprised at how many people ask about that key-switch in the rear panel on the early cars, and the switch on the front fender of the later cars. "What is that for???"
The best answer I ever heard was that someone had done some bodywork on the rear, and just neglected to put the trunk back in!