Horn not working because of dodgy fuse board

[BXMad]

A recent issue with my horn not working has highlighted potential issues with the fuse board. Its a bit of a long story but the issue may help others with mysterious electrical issues!
The horn had been working intermittently since my last MOT a year ago when I replaced the horn. MOT is just a week away, so I did all the usual checks; and the horn would not work. No amount of fiddling with the stalk switch made any difference. Assumed, it must be a bad earth.
So removed the bumper and checked the horn connections. Earth was fine, but no 12V!
Next thing to check was the switch. I filed-down two flat spade connectors/wire, to hook up my meter whilst I pressed the stalk. Made the connection to the two white connections on the 6-way plug (N.B. if the battery is still connected, remember that one of the wires is live with 12V!). Switch was OK, so then checked continuity to the horn with a 2M stretch of wire. It seemed OK but there was more resistance showing than I had anticipated. So checked, the horn worked by bridging the two whites. I got a crackly beep. So I checked the +Ve white (lower right looking at the plug from the bottom) and found variable voltage from 1 to 10v. Grrr.....
That meant chasing through BOL diags to see where it gets its power from on the fuse board. Turns out it’s the yellow 3-pin plug on the bottom right. Checking the fuse board connection spade used by the connector, showed 12V. So I checked the white wire for continuity and found .1 ohms. Good, but puzzled. So plugged the yellow connector back in to the fuse board and checked volts at the switch plug. No volts!
Unplugged the yellow connector again and checked the fuse board pin. 12V but then noticed that when I reduced pressure on the pin, it went to zero !!
Luckily, my TD doesn’t use the second relay (no rear electric windows), so the solution was to use a wire plugged into the lower pin and connect to the left hand socket of the yellow plug. Then made another wire from the yellow plug’s central connection to the fuse board.
Obviously this is a bodge and will need to fit another fuse board.....Morale of the story is beware of the fuse board!

[saintjamesy89]

Could removing the yellow FB connector and inspecting the spade inside the yellow housing help at all? The spades are easy to remove and inspect. Perhaps the spade needs tightening up for a better connection to the FB.

[BXMad]

Thanks for the suggestion but the lose connection is the male spade on the fuse board. It doesnt make any connection until its gentle pressed on one side. As the fuse board is made up of two circuit boads sandwiched togther, I believe its impossible to separate them to resolder the duff spade. I've owned BXs since '85 and this is the first time I've come across the problem. Luckily there was a relatively simple solution and I have a spare fuse board - which is hopefully OK