Yesterday was like a normal day . I started up my 914/6 Tribute ( original 1975 914 with a 1974 911 6 cylinder transplant running on Webers ) , ran down to the fuel station in daylight , turn indicators work fine . Came home and discovered that ;

horn does not work
clock does not work
sidelights do not work
headlights do not emerge ( but high beam indicator light does)
hazard lights do not work
windscreen wipers do not work

What does work is ignition light , starter , and turn indicators

Had a look at the fusebox which is aftermarket with blade type fuses , random checked a few fuses eg headlamp motor , parking lights - all ok

So I guess there is no power supply to those circuits into the fuse box if fuses OK

All I can think of is that some multi lead part of wiring harness has come unfixed but where do I look , I dont fancy pulling spaghetti out in case car ceases to work altogether !!

Advice please - my specialist is 80 miles away but will drive it there as a last resort

When you checked your fuses did you use a test light or a DVOM?

If you were using a test light and you had power on either side of the fuses you checked power supply as well.
Your problem will be weird affecting as many circuits as it has.

I don't intimately know 914 wiring yet but if you lost a bunch of circuits in anything I'd first look at ignition switch as it is usually the "gatekeeper" for power supply.

I'd check battery connections next and then I'd pull a wiring diagram to find out where all those circuits came together.
Fuse box/relay board would be my next targets...

Check the ground points as well, perhaps something came loose due to vibration or a corroded fastener or wire. There are a couple up under the dash as I recall and there's a diagram on here someplace or on https://bowlsby.net/914/Classic/TechNotebook.htm

Is it possible that it might be rodent damage?

Missed the grounds.

Grounds will mess with you bigtime.

Generally the hazard light circuit is one of the most robust and least encumbered, ditto the horn, at least in cars as old that this one. Seems like time to dig out your multimeter. Since no fuses are blown, the break in the circuit is possibly up stream of the power block vs downstream. Hard to tell how far your feeds differ from the norm given the engine swap but a quick Google of 914 wiring schematic will turn up the originals which is probably where you should start.

Some one else had a similar problem and it was internal in the aftermarket fuse block.

Also check the red cables attached to the positive battery terminal for a good tight clean connection

I understand how frustrating chasing wiring issues can be. Clay has been helping me with a few buggy things.

Hang in there. Go slow. Be methodical. Do you have a set of wiring digrams? (The FSM has beautiful color copies.)

thanks guys !

dr914 nailed it , it was the battery connection to 4 red cables coming away from the positive terminal - nothing was apparently loose but a tightening of the securing screw resulted in the clock ticking again and all systems were go !!
Here is the offending partClick to view attachment

I would get rid of that positive battery clamp ,this type corrode and cause a poor connection ,you are better of with a crimped and sealed type.
Cheers.