MTFCA Forum

What would a 4 wire switch harness be for?
Dash switch, non starter, mag headlights and horn car or truck?
I use to know but not sure now. Here is a picture How about a 4 position terminal block. One terminal marked bat.
Thanks, Dan

Is it long enough to run from the tmer to coil box for a pre 1915 car?

17” long plus about 5 more for the long single wire. Only 4 wires total.

Looks like a 5042 19-25 switch harness, but less wiries. I suspect its 19-25 non generator switch harness.
SWAG. That would explain the fewer wires.

Lang's shows Commutator wire harness, (5 wire), for cars with electric headlights and no starter, original style. I

TRDxB2 wrote: ↑

Sat Jan 03, 2026 6:45 pm

Lang's shows Commutator wire harness, (5 wire), for cars with electric headlights and no starter, original style. I

There is also the wiring harness for timer to coil box (26-7) mounted on the motor. (My first thought)
But the wires are different lengths @ the ends, same as you show from langs.
Not a close match. The switch wire harness wires shown (Dan's) are the same length on both ends mostly, hence my semi-educated guess.

There used to be a 4 wire switch harness sold. Need to find my old Langs catalog.
This one came out of a Ford dealership in the 60’s.

Dan's loom shows the problems with original wiring. The rubber insulation hardens over time as it deteriorates, and breaks rather than flexes. See the two sharp angles in the long lead. It is nice to see an original loom tag still in place. They do appear to be woven into the loom, but I believe they were fitted once the loom was woven. The alloy tags have a long taper one end. When I removed the original tags from each of Henrietta's looms, I inserted a blunt blade in the woven cover to push aside the fabric enough to slide the wide end of the tag into the weaving. The tag was bent into a U shape and the tapered end inserted into another parting of the loom cover and flattened out fit. It was more difficult with the brass tag on the under dash switch loom.
I have found a couple of looms with a plain rectangular steel tag simply bent around the loom. Easier to fit.

Allan from down under.

The 4 wire switch harness was used on the earlier starter/generator cars. The harness did not include the amp wire.There was a separate wire from the cutout to the amp meter. A 5 position terminal block was used. I have a NOS harness like yours in same condition. My 1920 Sedan was fitted that way. Here is a picture of the earlier wiring diagram. Les

Les: That was what I was thinking. I did have a few of those 4 wire harnesses. Must have sold them?
They are not much good except for the tag or pattern. But since they were only used few months, not much demand.
Most if not all NOS harness are in the same condition. I had quite a number at one time. All sold for the tags.
Thanks for helping ID this. Dan

I bought a bunch of those at Hershey once just to get the tags.