Photo by Uni Moe
so my son bought a 72 camper special and the PO put a column out of a 77 into it. I’ve been fighting it for awhile now and in retrospect I should have just bought a new column or at least the correct harness/ switch for it but I’m broke, so there’s that...anyway, the PO cut the 77 harness after the male end of the coupler and wired like colors together to the 72 harness. No brake lights, turn signals or flashers (the front emergency flashers work) also running lights work in front and back.
while searching the forum I found an old thread with a possible solution by Uni Moe, but I’m not sure I’m reading him exactly right.
this is his picture and it looks like to me you go :
yellow and black from 77 to blue and yellow on the 72
Dark green from 77 to orange and blue on the 72
Dark blue and yellow from 77 to Navy and Yellow on 72
light green and white from 77 to blue and white
White and blue from 77 to white and blue
Light Blue on 77 to Navy blue
Red and black on 77 to Dark green
blue and red on 77 to custom attach to dash lights

then white and red from 77 to maybe another white and red?
also not sure what you mean by “2 plug and 5 plug”
Uni Moe, if you’re out there and can confirm this, you’re my hero!👍

(later that same evening... Added some details as I found them. Should be mostly correct, but there are some discrepancies.)

I'm kind of winging it here, so bear with me a bit. I did not count the wires or verify their colors yet (which might narrow it down) but does your '72 have a horn relay, or is the horn wired directly through the horn button?
One way to tell on Fords is whether the turn signal switch has one contact or two. These are the brass-tipped springy thingies sticking up under the steering wheel.
Another way to tell would be to look under the hood, but I'm not sure what a '72 relay would look like, if '72's even had relays available (which I think they did) but it's worth a look-see around the engine compartment anyway. If for no other reason than to know what you're dealing with.
On Broncos starting in '74 the relay was a 3-wire metal shelled rectangular affair with a single screw holding it to a sheet metal surface for grounding. A Yellow wire is usually running straight from a battery connection, often at the starter relay.
Does the horn work by the way?

(edit: Looks like at least some '72's had horn relays, if not all of them. So we'll work on the assumption that you still have a horn relay and go from there)

The running lights don't go through the column, so they're separate from this search at the moment. The brake lights and turn signals and flashers do of course.
And by the way, I'm only assuming so figured I'd ask, but does your column have the hazard flasher switch sticking out the side? It should I believe, but not 100% sure.

While you're doing wiring stuff, as was suggested in another thread today, it's not a bad idea to (with the battery disconnected just because...) remove each and ever fuse from your fuse panel, wipe/scrape/brush the contact surfaces clean (even if they look clean) and then simply put the fuses back in.
Just the act of removing and replacing the fuses will usually clean up any oxidation from the contact points that can resist flow and cause you electrical headaches while hunting down other gremlins.

Yellow w/black is the Left STOP/TURN signal lamp.
Honestly, Blue w/yellow sounds like the horn wire, but I don't have a '72 diagram handy.
Gonna' bail out on you for a bit and hunt down the diagram. But posting what I've got so far so you have a few things to think about.

(edit: Yes, Blue w/yellow is the horn ground to trigger the horn relay. Does not sound like it belongs connected to the Yellow w/black to me)

Any chance that Orange is actually a faded/discolored White?

There is a second Blue w/yellow? This "navy" colored one is different from the other "blue" with yellow tracer?
I just don't see any other Blue-ish with yellow stripes. Only the horn ground.

Any chance it's White w/blue, instead of Blue w/white? White w/blue is the front turn-signal/dash turn indicator and runs through the hazard switch too.
Do the turn signal indicators work with the proper side? White w/blue and Green w/white are Right and Left front respectively.

Ok, well I guess that answers my question about the White w/blue. This sounds correct, but what are the others? I wonder if this is actually a '77 column and switch after all?

Just Blue is the power IN from the turn signal flasher. Nothing about light or dark in the book, so not sure if there was a change or not.

Red w/black is power IN from the brake switch. Should be matching colors for both years.
Green on the '72 "should be" the left rear running lights. Turns to Brown back at the lights to cross over to the right side.
This should be the same for both years, so again the the same colors should be connected it sounds like.

Blue w/red is the common color for dash lights and comes from the headlight switch, usually through a fuse in the panel to work the lamp for the PRNDL indicator.

Should be Emergency Flasher power into the switch from the flasher unit.
Seems correct to have them connected together.

I believe that he's simply referring to the number of wires in each connector plug. You can see that the 5-plug has five wires and the 2-plug has two.
So that's my assumption. Again, "for the moment and until a better theory shows up"

ALL F100/350, Bronco's and Econolines have a horn relay thru 1977, as do 1978/79's with Speed Control.

1978/79: No Speed Control, no horn relay.

1973/79 F100/350: Emergency 4 way flasher switch made as part of the T/S switch, button protrudes from the right side of the steering column.

1970/72: Emergency flasher switch located on the right side of the steering column (see pic below).