MTFCA Forum

I’m curious about the wiring process used on metal dash Ts.

I’ve seen videos of wood dash cars having the bodies dropped onto the chassis and just a bit of connection work done before the complete car is driven away. I noted that the wooden dashboards are in place on the chassis so all the wiring was completed before the body is slipped into place.

The metal dash on our 1927 Tudor isn’t part of the chassis so I’m wondering when the wiring was completed for these later cars.

I don’t think all the wire connections were done after the 2 major assemblies came together so am wondering if the dashboards were completely wired to the chassis and then connected to the body when it was dropped into place.

I’m asking out of curiosity but also because I have this wiring chore ahead of me and would like to know how Henry conducted the process.

Many thanks for your thoughts - Joe

Joe - not sure how the factory did it, but I recently rewired my ‘26 RPU - every cable and wire including light sockets and thimbles. Pretty straight forward job - chassis wires to terminal block; wired ignition/light switch loom through the dash and firewall hole to terminal block.
I don’t know if the Tudor is more complicated than the Roadster, but I’m sure you will get plenty of support on the forum.

The Improved Car simplifies install of wiring as the coil box is on the engine and all wiring for the chassis is on the chassis , battery and cables too before the body drop.

So undoubtedly the switch wiring to the combo switch on the dash is done, and the 5042B switch loom run to and fitted on the terminal block on the firewall.

All that was needed is to wire the lighting wire harness 5041E to the block after the body drop.

You didn’t mention if you are restoring the car or just wanting to rewire it as it is. Either way it’s pretty straight forward on a completed car restored or not.
Wiring diagrams for T’s are readily available so you can follow it and the wirings sets are color coded.
If your rewiring the car do one harness at a time. Usually there is one for the timer generator, one for the coil box to ignition switch and a lighting wire.
I may not have listed them exactly as they should be but you can go to a parts suppliers catalog or page and order the wiring sets for your paticular car,

Take off ONE wire at a time and use the new wire and so on and so on. You can’t go wrong just take your time.

This restoration has been going on for almost 60 years now and retirement has given me the time to finally get at it. This is a frame up recovery process and it's moving at a super slow pace.....but still a lot faster than during the previous 55 years.

There is no original wiring remaining and I have a new set of wiring ready to be installed and connected. Checking the older car videos, I noticed that the wiring was all in place before the body was attached. I couldn't figure out how the newer metal dash cars were slipped together so quickly without having a lot of the system prewired. Henry must have figured out how to do the wiring efficiently and with maximum time saving. If it worked for him, I figured that his system would work for me too.

When I wired my '25 I looked at each photo in the service book to make sure I had every wire placed exactly like Ford did. I also had genuine Ford looms reproduced exactly, with the original Ford tags woven into the looms. Perhaps the looms have improved since I restored the car ten years ago. I ordered a set of looms from Langs that were supposed to be show quality, and wasn't happy with them, and gave them to someone else who isn't as fussy as I am.

This is a clip from a YouTube video
I don't think it matters if its wood or steel in this photo because the assembly process wouldn't change for this shape firewall
Ford Model T Assembly Line (1919) https://www.youtube.com/watch?v=Pf8d4NE8XPw --
This video show placement before the body is put on
1920's Model T Ford Cars Being Manufactured https://www.youtube.com/watch?v=4e3orWGmQ-o

I think Steve Jeff makes a good point about wiring on the 26-27 cars. Most of us who restore Model T’s use Fords methods to a certain extent when restoring Model T’s. Frame, axles, engine first. Then different aspects of the body assembled on the frame.
Ford was wanting to the do it fastest way he could on the assembly line for production.
We aren’t trying to match every way that Ford did it but still doing it in sub assemblies at some point and a lot slower.

As far as the wiring is concerned it can be done on the body after it’s put together or before as it was done on the 25 and back cars since the firewall was separate. But it still can be done after the firewall is already mounted on any T. Separate firewall or not.
Every thing is relatively easy to get to and that makes it pretty straight forward.

Original Smith, you have me a bit (well, more than a bit) concerned about wire quality.

I have a complete set of Lang's wiring looms on the shelf ready to go when there's something to connect to but your comment about the quality causes pause. What should I be looking at for shortfalls and what would my wiring option be if I tossed these looms out?

Many thanks for any thoughts,

Joe

You're going to be fine. If purchased from Lang's, then use the loom you purchased with no fear, unless you are worried about someone from CA confronting you at a car show claiming that the thread count on the loom is not per original. In that case, if not the loom, it would be something else.

While you're doing it, strongly consider the addition of a single 25A in-line fuse that Lang's also carries...it is cheap insurance. If anyone makes an issue on this subject to point out that blowing this fuse while driving will cost you a generator, then you can add a small fuse to the generator's field coil and tuck it inside.

Only issue in harnesses I have found. Some cheaper looms are crimp only terminal ends.
Make sure your terminal ends have all been soldered, otherwise they will eventually oxidize & loose contact.

I am quite relieved to hear that there should be no worries about the Lang's wiring looms but now I"m getting worried about being called out by a CA authenticity expert. But, then again, I'll never travel that far in this T so perhaps I should worry about other things instead.

The comment about soldered ends will be addressed as this restoration process is a lot of work and I don't want to have to come back to repair &/or replace work that I'm trying to do as best as I can. Do it right and do it once was sound advice that I've gotten along the way.

I did order the inline fuse when I sourced the wiring, again following expert advice. Seemed like cheap insurance and, even if not totally authentic, it could help avoid some bad outcomes. Hard to argue with wise T folk especially when having virtually no experience in most things regarding the mysterious Model T.

...BOT....

When I restored my '25, I used the Ford Service book as a guide for the location and routing of all the wiring.

Rewiring a T is pretty straight forward. Follow the diagrams in the Ford Service manual or numerous others that are out there. You probably could rewire the ignition switch first. If you can get to the ignition switch easier do that since you have a 27 Tudor. You necessarily don’t have to rewire your car the exact steps Ford did but from an assembly line he did it the fastest way he could.
Simply follow the wiring diagrams and you can do it any way you want to. T’s have been rewired countless times with the car being completely together.

You’re trying to reply to an over 2 year old post!

As Scott noted. …BOT…!

The poster who brought this thread back to life is using ChatGPD. He entered the first sentence of the original question and ran this reply in AI. So that is the odd post that re-surfaced this thread!!!

My WAG on this is someone somewhere asked a question to the ChatGPD bot, it found us, and now it's decided to spread it's unfailing wisdom to the club...

I'm still working on the wiring for this 1927 Tudor but the body isn't ready to go on the chassis. In the interim, I've constructed a wooden firewall that holds the wiring and a small temporary gas tank so the engine can be operated and, hopefully, I will be able to wobble up and down the street.

My original question sprung from watching old films of Model T factory construction that showed the bodies being dropped onto the the frames and the cars being driven away almost immediately. This worked well when the firewalls were already in place on the frames allowing the wiring to be in place before the bodies went on.

However, the metal bodies with attached firewalls have all kinds of wiring connected to the chassis and the body so I wondered when the various wiring components were installed and connected to ensure the quickest assembly line process.

There are some valuable and insightful comments above and I thank you all for your ponderings and observations.

Joe

The Improved Car '26-'27 came along with improvements to assembly line too.

As for your wiring questions, the chassis was wired at ignition, and lighting looms as it chain drove down the line, note the 15th Million, coil box on engine, wires to plugs and timer already on the engine during engine drop.
The body was fitted with the switch wire loom before the body drop, as dash and switch plate were in prior.

Note the switch loom sticking out the firewall as the lighting loom headlamp wires dangle below the lamps
Lastly would be the tail lamp wire to the rear fender. Battery and starter foot switch loom would have been installed on the chassis.

Closed cars would be done the same.

Thanks for the photos Dan ! I noticed the modification to the manifold side of the engine picker to "clear" the Vaporizer carburetor - don't believe mine will do that !