2 black wires in fuse box...

[qcetc]

Hello everyone, I'm sure this is old but could not find out anything so here it is. Don't laugh. I'm sure you already went through this!
Can anyone tell me where the 2 well actually 1 wire goes with a pigtail in the fusebox. I thought it went to the first connector and 4th. But when I hook it up this way the lights stay on all the time and the horn works. when I unplug from the 4th connector the lights go off but the horn does not work at all. Is there a good picture of the fusebox with wire colors anywhere. I have a 76 spider.
Good news though...went for a ride today. First time since I bought the car, about a year ago.

Just said the heck with a bunch of wires and went with some stuff not working. Turn signals, heater etc... But I would like to get the horn working on the right fuse.

Thanks
Rick

[seabeelt]

I have a 78 so not sure if the diagram is the same. there should be a violet wire from the horn relay to the front side of fuse #9 and the two black wires go to the back side of fuse #9. There is also a violet wire running to fuse #10 and a black wire on the back side of #10. it looks like the diagram has the back side of fuses #9 and 10 tied together so either may work. Good luck and let us know how it turned out.