1977 Highboy with a 351m that I’ve been working on slowly for a couple years. It was a real mess when I bought it (but of course didn’t find that out till I started messing with it. Seemed nice when I bought it). It currently runs like a dream. Minus some cosmetic and electrical issues.

I’ll be honest, electrical work is not something I understand very well

The previous owner really screwed up some of the wiring. Like used house wire for the tail lights kind of thing. So half the time I’m wondering were a loose wire came from. I’ve replaced most of the exterior sockets and they are all working properly finally, but the interior really needs work.
Previous owner wired a button for the horn onto the dash, so when I replace the steering wheel (he put a GMC one in it), I would like to make that work properly INSIDE the steering wheel. The horn only works when the key is on?
I recently bought a gauge cluster (I know it was working when I ordered it via video), my 3rd one. Put it in today. The turn signals work, as well as the blue light for the brights. The brake light is on %100 of the time. None of the back lights(inside the gauge cluster) come on but bulbs are good... the speedo is not moving and neither is the fuel gauge (also, does anyone know where to get an original fuel sending unit for an in cab tank or do I HAVE to convert to something more modern?). The oil pressure, temp, and battery gauge are rerouted to aftermarket gauges located below the dash (they work). The alarm for my seatbelt comes on for 10 seconds when the truck starts up but the light on this cluster doesn’t turn on. The last gauge cluster I tried, that was the ONLY thing that worked. The dome light above the seat also has never worked. Exterior lights and wipers do. All fuses are good.

Recently the Kenwood stereo kept blowing fuses (in the radio) for no obvious reason, and I need to replace that as well now.

So I guess my question is, where do I even start in figuring out my gauge cluster issues? The speedo was installed by a mechanic about 4 months ago but without a working gauge cluster at the time we couldn’t test it. It was new so I assume it works. Could I have damaged it while I was either taking it out or plugging it into the new cluster? When I bought the truck it didn’t have a cable at all.
Where do I even begin on the dome light?
the fuel gauge?
the fuel sending unit rusted out in the tank, but even when I move what’s left of the bobber, I get no reaction from the gauge. I do not have dual tanks.
How will I get the horn back into the steering wheel?
Like i said, wiring is not my forte so I really don’t know where to begin.

 

Look for an EVTM for your model year. Good resource for wiring issues.

 

All my elec stuff starts here. https://www.ford-trucks.com/forums/1...l#post14696846

Dome light info. https://www.ford-trucks.com/forums/1...l#post14696878