1928 A headlight and horn wiring?

1

1EarlyA

Senior Member
Several owners ago, when the old engine was removed from my '28, they just cut the headlight and horn wiring to remove the light bar. Of course they didn't mark anything.
I know which 2 were the horn simply by the length. But, I don't know which wire goes to which in each of the pairs. I suppose, since it is only 2 wires per item, it would be a relatively simple trial and error if that were the only factor. But, I believe there are some other electrical gremlins as someone had made a cardboard shim to go between the column and the headlight switch. I made the mistake of pulling that out and now the switch flops around a bit. I really don't even know about the function (or lack thereof) of the switch.
Additionally, there is (I assume) a short somewhere. I don't know if this has anything to do with the lights / horn, or if it is a separate issue. With the battery connected but the engine not running, it shows a roughly 10 amp draw. Once I start it up it charges great. So, up to this point, I have just unhooked the battery when I'm not running it.


Any words of wisdom would be great. I really hope this isn't going to require much more money because I'm already into it about a grand more than I originally intended.


Thanks in advance.
 
Wiring diagrams exist - and the diagrams are "color coded" to tell you the right wire to the right location.

Although if you're like me, any of the early/original wire harnesses you find are more valuable in scrap copper than their read on what the wire coloring/purpose actually is.

In examining the wiring diagrams, keep in mind that Ford underwent a fairly radical change to the headlight wiring about March of 1929. Before then headlight were "type H" lens (a hold-over from Model T) and a single two filament bulb was at the center of the reflector.

After March 29 the reflectors have TWO bulbs. "Twolite" system. One two filament bulb at the center and one single filament bulb placed off center.

If your car is 1928, then you're probably the earlier setup. That is unless someone has been there ahead of you and converted everything, or even parts of it, over. The problem with the early setup is that there are few parts being made for replacement. Most people tend to replace with the later setup - and possibly "dead end" wires as there will be more wires than need if your system ends up "mix & match."

I'm currently working on a 1928 AA truck. The headlights are early (with go figure twolite lenses) The light switch is missing. It takes a (so called) "Four contact switch" which are only available on flea market tables or Ebay - when you can find them. But to do the wiring will be my challenge.

Right now I'm planning on buying a new twolite wiring harness, taking the wires/loom as I need it in the correct colors, and soldering to the earlier type H switch plate.

And following the earlier wiring diagram for colors.

That way I end up with the "park-off-hi" at the steering wheel switch control. A later switch/plate/twolight setup gets "park-off-low-high"

One of the conundrums of the Model A is encountering/learning about/finding ways around changes made by Henry Ford during original production

Wiring diagrams AND a useful how to "primer" on Model A Ford wiring is found at https://www.lionsgatemodelaclub.com/Reference%20Info/2018%20Reno%20Electrical%20System%20Alex%20Janke%20%281%29.pdf.

Joe K
 
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If you have the Twolite system, the low beams have the filament on the top of the bulb. Knowing this makes it easy to check the wiring. Many owners have abandoned the connector at the outside of the headlight bucket in favor of individual connectors inside the bucket.

Most Model A owners have a battery switch to easily disconnect the battery when the car is not being used. It is also a safety measure.

Finding a short can be as easy as disconnecting circuits one at a time to find which circuit has the short. 10 amps sounds like it may be your brake light switch.
 
One of the weakest parts of Henry's lighting system is the "bayonet" connectors - which are a kind of "take" on bayonet sockets used on the bulbs.

I generally DON'T use the cylindrical/slotted insulator/separator blocks. Today's wiring typically has "crimped on" contacts at the end. These don't fit the separator blocks well. An alternative (and originality) is found to remove the crimped on contacts and solder on turned brass "caps" - which work and do improve somewhat on the reliability of connection.

HOWEVER, my solution is to cut off the ends, bare the copper, and use a crimp on insulated connector on both the wiring loom AND the wires in the lamp. Akin to the "you'll need a wire crimper" comment above. Which you do - but once made and covered up by the stainless conduit/collars, you won't know it from original.

It also leaves room for a reliable "ground wire" going from the reflector back to the frame of the car.

AND - it stays "working". No "winking" at the oncoming automobiles.

Joe K
 
Joe K said:
Wiring diagrams exist - and the diagrams are "color coded" to tell you the right wire to the right location.

Joe K
Click to expand...


I'm certain this wiring was replaced when the car was restored in the 80s or 90s. Both wires that go to the left headlight appear to be the same color and both wires that go to the right headlight appear to be the same color. I am afraid I will likely end up tracing all the wires end to end to figure out what goes where. I asked here first because I hoped someone more knowledgeable would have an "easy" answer.
 
First is obviously to determine what exactly you have. I've told about the differences between "Type H" and "Twolite."

A switch just came up on Ebay for the Type H circuit - I last left it at $43 and it probably sold for the better part of $100. Two months back I paid on Ebay $99 for a Type H switch - but that one had the "circuit plate" still in it - and the wires cut cleanly (not butchered) I'll have to come up with wires - to modify a twolite harness seems easiest for me.

You can buy Twolite components for as little as $15 for the switch body - the Twolite wiring (with plate) will set you back nearly $150. But you'll see the color coding and all the circuit diagrams are well documented.

It is possible to put a Twolite setup onto a Type H headlight - you simply end up with a dead wire going to each headlight - and at the steering column you'll have park-off-nothing-high. Or possibly off-off-low-high, depending on which wires you use and how you connect them.

As I say, learn about the differences and the implications for each of the two wiring systems.

It may be easiest to head for a twolite variant. Its probably what a Ford Garage would have done in 1937.

Joe K
 
This may be a dumb question, but does it make any difference (just in general) that my ground wire goes to the transmission instead of the frame?
 
1EarlyA said:
This may be a dumb question, but does it make any difference (just in general) that my ground wire goes to the transmission instead of the frame?
Click to expand...

Probably not.

Ground wire for starter is the case of the starter. I.e. Flywheel housing. Ditto the generator. I.e. engine crankcase.

The big thing in the case of headlights is to get away from an at times "flaky" connection between headlamp reflector and headlamp shell. Another flaky connection between headlamp shell and headlight mounting bar. Another flaky connection between headlight mounting bar and fender bracket. And a last flaky connection between fender bracket and frame.

To go all the way back to the battery strap attached to the frame would be ideal. But then the question arises to the cable clamp to post connection?

Real world with real world limitations.

Joe K
 
Joe K is correct about all the connections. I removed the connector between head light shell and the flexible connector and replaced with bullet connectors on both ends of the wires going from the bulbs to headlight wiring harness. I also threaded a separate ground wire from each headlight bucket to frame ground inside the flexible conduits. Did the same grounding for each of the tail light buckets. Finally added an extra ground from the engine to the frame. The bullet connectors were soldered to each end of the wires and there are connector sleaves that accept bullet connectors at each end. If the headlight bucket ever has to be removed, it easily comes apart.
 
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