Horn doesn't work. Relay clicks and fuse is good.
When I measure voltage at the horn connection, I get like .2 volts- pressing the horn barely moves the meter.
How many volts does the horn need to work?
I'm about to go pull the horn and test it straight to the battery.
Thanks.

Edit- just occurred to me that I may be measuring the volts wrong. I measured from pin to pin on the horn connector. Maybe I need to measure from the pin to a ground? Not sure exactly how a horn is supposed to be wired. Off to google I guess.

 

Depending on which 2 pins you are talking about, you are correct.

The horn connector ( C136 ) is a 2 pin connector, yellow w/ light green stripe and a black.

Black is ground, and the YE/LG is the output from the horn relay.

So if you pull the connector off the horns, hook a meter to the black & YE/LG, you should have 12+ V.

This could be in a few places.

Quick test, pull the horn relay, and jumper pin #3 to Pin #5.


This will remove the relay ( coil activated by the horn switch on the wheel ) and take power direct from Battery Junction Box ( aka BJB / engine compartment fuse panel ) fuse # 7, direct to the horns.

If this works, you could have a problem with the relay, or the horn switch.

To bench test the relay, hook you meter in ohm setting to pins #3 and #5 ( normally open contact ), and apply power to pin #1, and ground to pin #2.
The meter should show very low resistance ( 0.2 to 5 ohms ).
If not, you have a bad relay.
If it does, time to check the output of the horn switch.

Hook your meter to ground and to the relay socket pin #2 ( drawing above, looking at the relay socket ) with it set to resistance.
Push the horn switch on the steering wheel, the resistance should be low ( 0.2 to 5 or so ohms ) if not you have a problem with the horn switch or clock spring.

You can also test from pin #3 in the relay socket to ground with the meter on voltage, and you should get 12+ V.

Those are the basic tests, and should cover it all, let us know what happens.

 

Got it sorted out.
When I initially checked voltage at the horn connector pins down by the bumper, I didn't fully make contact with my meter leads. I discovered that I had 12 volts at the pins, so I went and bought a low tone horn from discount auto. Wired it up and now I can make noise again. But damn, the low tone sounds pretty high and wimpy to me. And it wasn't exactly cheap at 16 bucks.
Next time I will get a couple of junkyard horns, but for now I'll be honking like a mid-sized sedan.
Thanks for the help- the relay diagrams and other info was interesting, and I have saved it for reference.