Ground Connection

[Original Smith]

I'm trying to assist a friend with a 1915. Is there a separate ground connection for the headlights, or is one of the fender bracket bolts used?

[mtntee20]

Larry, I believe the ground is through the headlight bucket to the support rod, to the frame, as there is no third wire on my headlights.

As the model Ts are notorious for bad grounding, I plan on adding a wire from the bucket to the frame, making sure those spots are paint and rust free. Once completed to my satisfaction, I will paint OVER the connections to 1, cover them for visual concerns, and 2, to prevent rusting. I am going to add a ground cable (NOT A STRAP) from the engine/starter to the frame, cleaning to bare metal, making the connection, and then painting.

[DanTreace]

Most diagrams show to ground to radiator mounting stud nut for magneto bulb 1915 headlamps.

[George Mills]

Larry,

If still magneto …. The ‘ground’ is the wire that does NOT run across the radiator tube, it’s the other one from the lamp connector. This one for ‘correct’ purposes runs down and is held by the drivers side, radiator support stud.

Sorry, Dan beat me by a few seconds…lol…can’t delete

[Erik Johnson]

Ground wire from headlamp socket to radiator stud as Dan posted - this is my father's 1917 Ford.

From the factory, supposedly the ground wire from the headlight was actually soldered to the radiator support. Don't know if that was how it was done on the Rip Van Winkle 1917 touring - I have a number of photos of that car so I'll have to look to see if any show that.

[Steve Jelf]

This worked for me, and I think it's "approximately correct". The wire on the right brings magneto current that has passed through the right headlamp and feeds it to the left headlamp. The wire on the left brings current from the left headlamp to ground at the radiator stud.

[hull 433]

The ground on the Ghost connects to one of the engine pan bolts on the forward frame. I've never questioned it but don't know if it's right. I looked for examples of ground wires to radiator studs but found none.

Here's a 1915-16 Ford factory photo showing a method of towing. The ground is somewhere else on the car, not on the radiator stud.

[TRDxB2]

I'm trying to assist a friend with a 1915. Is there a separate ground connection for the headlights, or is one of the fender bracket bolts used?

The connection of either the headlight adjusting screw and/or the lamp socket to the headlight bucket should be checked.
One question: Is the wiring for the lamps in series as the diagram says
Corrected the diagram Ground wire connected to radiator support

--
--

[Erik Johnson]

Frank:

Your diagram does not apply to a stock 1915 Ford.

[TRDxB2]

Frank:

Your diagram does not apply to a stock 1915 Ford.

Woops wrong diagram thanks for noticing add the correct one above

[Steve Jelf]

No questions bout it: The 1921 diagram says the Head Lights are grounded through the lamps.

Larry asked about 1915, not 1921 or later. They're not all the same.

1915 headlamps are wired in series, like old time Christmas tree lights. Both headlamps are powered by the fifth wire in the commutator cable. The current comes directly from the magneto through the light switch on the firewall.

[Original Smith]

What exactly is the radiator support? I don't understand how the stud that holds the radiator to the frame would provide a very good ground? The best one I've seen yet is the one that shows the ground to the front engine dust pan bolt.

[TRDxB2]

What exactly is the radiator support? I don't understand how the stud that holds the radiator to the frame would provide a very good ground? The best one I've seen yet is the one that shows the ground to the front engine dust pan bolt.

I would say its what Jeff's picture above shows, the radiator mounting bolt.

[Erik Johnson]

You may ground the headlamp wire to whatever you please.

The radiator support is the strap/crossbar/bracket towards the bottom of the radiator - it has a hole at each end so you can mount the radiator to the frame.

It is my understanding that from the factory, the ground wire was actually soldered inside the engine compartment to the radiator, specifically soldered to the radiator support/crossbar/strap/bracket. Most likely, that connection came loose over time or it was cut when the radiator was removed for repairs or replacement. Then the logical spot would be to attach the ground wire to the radiator stud instead of resoldering the wire to the radiator. In my photo above, for a neat appearance, my father installed a ring terminal on the end of the wire, the inner diameter being the same as the radiator stud.

When I have some time, I''ll see if I have a photo of the ground wire soldered to the radiator on the Rip Van Winkle 1917 touring.

[Steve Jelf]

I'm with Erik. My photo above doesn't show it, but the ground wire ends in a ring terminal under the nut that fits the stud. This ALWAYS worked, and NEVER gave me any trouble at all. How many fairies can dance on the head of a pin?

[Erik Johnson]

Here are photos of the "Rip Van Winkle" 1917 touring - click on photos to enlarge. This car has a June 1917 motor number and was most likely assembled in the downtown Minneapolis plant.

The wire is grounded to the radiator support strap. The yellow arrow points to solder blob which actually extends downward past the support strap and onto two or three fins below.

Why Ford Motor Company engineers decided that the headlight should be grounded in this manner is a mystery.

[RajoRacer]

Boy, if that's not the best documentation ever !!! Thanks for posting that photo, Erik.

[Erik Johnson]

Credit should go to Trent Bogess.

It was due to one of his posts years ago that I became aware that the ground wire was soldered to the radiator cross bar.

See this thread and read Trent's comment:

https://www.mtfca.com/discus/messages/29/24151.html

[TrentB]

Thank you, Erik.

Trent Boggess

[Allan]

Eric's second photo of the Rip van Winkle 1917 car raised my interest. The wiring exiting from the engine compartment looks like a problem in the making. Perhaps it should be exiting from under the hood shelf via the cut off corner on the outer edge of the shelf, rather than where it is shown.
This hood shelf is another variation to the low radiator type. I have seen one with a small single wire hole punched in the top surface of the shelf at the front. This one had a raised ring around that hole.
Then there was this one.

I was given a pair of these, with the odd shaped hood hooks. The inverted U shaped relief in the outer side of the shelf is likely there to accommodate two wires on later cars.
Then there was the later type with the large hole on top, and the hard rubber grommet to stop the wires chafing on the panel.
So that makes four variations now.

Allan from down under.

[Original Smith]

I am finally learning from this post the way Ford grounded that wire, and I'm not pleased! Keep in mind, the brass cars had the radiator laying on a thick leather pad. No grounding there. But the studs did go through that pad and to the big square nut and coil spring which would make a pretty good ground. I believe if I had a 1915 I would crimp and solder a connector to the end of the ground wire that would be placed between frame and the coil spring.

[J1MGOLDEN]

I never knew that either, but I had to run a complete set of ground wires on a 1926 T Roadster to get any of the lights to work.

[Moxie26]

True CLEAN metal to metal contacts will conduct electricity. Paint acts as an insulator.

[TXGOAT2]

Paint, rust, dirt, and any kind of corrosion will interfere with an electrical connection. I'd think the radiator mount bolt/stud would be a less than reliable ground point since it is not actually tight on either the early cars with a leather pad or the later ones with the springs and thimbles.

[Trford]

My 1915 Touring headlight ground wire. Note: cross tube and wire not shown. Needs to be repaired. I don’t know this to be original. For your reference.

[George Mills]

The family ‘15 has always been thought to be mostly original so I had the current steward the youngest son take a look. None of the above, whatever…no solder stains anywhere on the brass…the ‘ground’ wire comes back thru the clash strip grommet, runs under the clash strip and pops out by the hood former where the wire seats under the nut holding the body bracket. Just sayin…while it has probably changed from as built according to the above post this one was parked and locked in the back of a Bell Tel shop in the late teens, was untouched until the mid 50’s, and was pretty much used as static display from when it was until I bought in 95. As my son said ‘option 6??’