I have a loose wire on the firewall, see picture. No idea what it goes to. Suggestions?
Is the "loose wire" the one that's hanging over the cylinder head?
Some cars had the Generator wire in the same cover that encased timer wires. I'd also like to recommend you get new wiring looms for you car and replace following the wiring schematics. When you do this you'll have everything with the proper colorers that ford used and will help you chase things down. Here are a few examples of what I went through.
NEW WIRE HARNESSES
Yes the loose wire is the one hanging in space that has the square connector on the end.
All I can suggest for the non-stock loose wire is try to follow it and see where it goes. I agree with George. Replace that mess with proper wiring, and follow the diagram.
Where does one obtain a new loom?
Lang’s, MA (978) 297-1919 www.modeltford.com
Bob’s, IL (815) 633-7244 ModelT2001@comcast.net
Snyder’s, OH (330) 549-5313 firstname.lastname@example.org
Chaffin’s, CA (951) 735-4791 www.chaffinsgarage.com
It apparently goes to nothing near the starter. Just a loose end on the other side.
My guess is the extra wire is a head light switch wire, like the 1915-1917 type loom.
The passenger headlight does not work. Maybe that is it. Hard to see that diagram, real small.
The 1915-17 cars didn't have any generator, so the headlamps were powered by the magneto. Your '24 with a generator is wired differently so it's not likely your non working passenger headlight has anything to with this loose wire. Probably it's just a burned out bulb. And maybe a previous owner bought a timer to coil box wire loom that was meant for a non generator car?
Those commutator and spark plug wires look like they've seen better days. I'd definitely toss them for new ones.
I respectfully suggest that you replace the wiring in your car. The wiring you have now is a fire or dead magneto waiting to happen.
I bought "Commutator wire harness (7 wire) original style 1919-1925" from Langs. Black/green, black/red have spade connectors on one end and stripped bare wire on the other end. Which side goes to the switch and which side goes to the terminal block? Also, is there a diagram which shows which color goes where? The diagram on this thread does not show Black/green, black/red but the 'after' terminal block does.
Pull all the old wiring and replace with new wiring harnesses that are readily available from most of the vendors.
Rewiring a T is fairly easily if you just start over and follow the wiring diagrams using the color coded wires.
Everything is easy to get to and figure out.
Start with the ignition switch and coil box wiring. Everything else follows after that.
When you do this you can learn a lot about how your T is wired and what to do if you have to trouble shoot it for any electrical issues.
You learn by doing.
The commutator wire harness has wires for the timer red black blue and green,1 yellow wire for the generator and 2 wires with bare ends for the headlight black with green and black with red. None of this harness goes to the switch. You may also need the switch to terminal block harness and the 5 wire harness for the drivers side light.
The generator wire is not solid yellow but rather is yellow with black tracer. One end of it connects to the cutout which sits on top of the generator. The other end of that goes to terminal number 1 on the barrier strip which is the leftmost terminal as you face the terminal block. It appears that wire has been replaced by a wire outside the loom. I agree with everyone else - the wiring on this car is going to be nothing but a constant source of headaches for you going forward and if you have a flaky connection in any of the 5 wires that make up the connections between that cutout device and the battery positive terminal you stand a good chance of burning out the generator field or armature and/or constant battery problems. Fix it ONCE do it RIGHT.
Ignacio, in my '26 (different wire harness, to be fair) black/green and black/red are for the headlights. Spade connector goes to the terminal block, the bare ends go to the headlights. It should be more obvious when you take a look at how the wires attach to the light sockets.