WIRING DIAGRAMS, Electrical system

[tbirdtbird]

Here is the same info presented in 3 different ways:

1 wire.jpg


Notice:::::: The two wiring diagrams below are pre NOV 29. All cars should be wired as shown above in the first diagram
SEE POST #5 BELOW!!!
3 wire.jpg

2 wire.jpg

[Beauford]

I'll need this soon for the lights....

[Mitch]

Scan0015.jpg

[JohnnyDeMichael]

Nice diagram of switch, but is the diagram showing the connection side of the switch or the side with the 9 bumps. I’m new the forum. My wiring is original but good. On the black disc that goes in the light switch housing, there is no connection for the horn in the middle. If it once had a connector, I don’t see where it would have been attached. In middle is just a circular cylinder that’s is split I’d the middle. Should I try to solder a connector to the side of it? Surely another way . . . ?.?

[Mitch]

You might want to start a new thread in the main Model A discussion forum
this may help?

https://www.vintagefordforum.com/forum/model-a/electrical-and-ignition-reference/73073-light-switch-spider-info

[Mitch]

Scan0016.jpg

[BillLee/Chandler, TX]

Here is the same info presented in 3 different ways:

1 wire.jpg3 wire.jpg

2 wire.jpg

Has anyone else seen that the terminal box wiring on the first two diagrams is different? Take a close look.

On the first, the feed to the ignition is on the side where the generator connects, whereas on the second, the ignition circuit is on the other side where the battery connects.

Bill

[Mitch]

Has anyone else seen that the terminal box wiring on the first two diagrams is different? Take a close look.

On the first, the feed to the ignition is on the side where the generator connects, whereas on the second, the ignition circuit is on the other side where the battery connects.

Bill

This change in wiring took place I believe in 1929. Vehicles wired the old way were usually switched over. This is documented in the service bulletins see attached

86DD4907-DE42-4608-ACCF-6D35F38829C2.jpeg

[BillLee/Chandler, TX]

Looks like the correct/current diagram is the second one. Or is it the first?

(Confusion abounds here! )

[Mitch]

The first is
The black wire from the coil will should go to the drivers side of the junction box. The drivers side of the junction box will then feed the passenger side of the ammeter.
Of course this is on a left hand drive vehicle

[BillLee/Chandler, TX]

"Excluding the starter, on a correctly wired Model A, the only current passing through the ammeter is the current into or out of the battery."

Is the above statement correct?

[Mitch]

The above statement is correct. Vehicles pre wiring change the ignition was not passing through ammeter. If the points were closed and the key was turned on the draw would not register

[BillLee/Chandler, TX]

Thanks, Mitch.

[Mitch]

E948E289-12FA-4610-BDAB-A3D29C783CEE.jpeg

[Mike V. Florida]

How come no dome light? What is their color and where does the power hook up?

[DaWizard]

Can't give you the wire color but it comes directly off the Junction Box. Black w/Red tracer comes to mind.

[Getgoof]

Just purchased a 1930 Model A.

Found this diagram with documents the previous owner had.

[Mitch]

Just purchased a 1930 Model A.

Found this diagram with documents the previous owner had.

Welcome Getgoof to the VFF!! Thanks for posting that wiring diagram to our tech thread. It is a little different from the others so thanks for sharing it. Feel free to do an intro and post pics of your new A in the main Model A discussion area.

[Mitch]

Scan0272.jpgScan0275.jpgScan0276.jpg

[Mitch]

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[Bud_D]

Question: On ALL the diagrams above, is it IMPLIED that the coil case should be grounded in order to work properly? I just had to replace a coil on my 6V 8N tractor to get it running. I ran across an old posting on a tractor website where a statement was made that the case of the coil needed to be grounded to function properly. I serviced the electrical system on the 8N in September, but went out last week (February 1) and it simply would not work until I replaced the coil. I am trying to understand if it lost its ground. Thanks.
PS, I don't think a coil case would need to be grounded.

[Mitch]

Question: On ALL the diagrams above, is it IMPLIED that the coil case should be grounded in order to work properly? I just had to replace a coil on my 6V 8N tractor to get it running. I ran across an old posting on a tractor website where a statement was made that the case of the coil needed to be grounded to function properly. I serviced the electrical system on the 8N in September, but went out last week (February 1) and it simply would not work until I replaced the coil. I am trying to understand if it lost its ground. Thanks.
PS, I don't think a coil case would need to be grounded.

Hi Bud
The coil casing does not need to be grounded