The Ford Barn

David in San Antonio · 04-01-2025, 04:41 PM

How do I install a disconnect switch in a Roadster with two ground straps - one to the frame, the other to a transmission bolt?
I need to understand both the wiring and how to mount the switch.
This may seem obvious to many of you, but I’m starting my Model A education from scratch. Thanks in advance.

Y-Blockhead · 04-01-2025, 05:01 PM

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David, connect the disconnect swith between the battery + side, if positive ground, and the frame. Connect the second ground from the where the first ground is bolted to the frame to the transmission.

There are several places to mount the switch. Mount it so it is convenient to you. I mounted mine in my Town Sedan just in front of the front seat.

I have a third smaller gauge wire running rom the frame to the headlight bar, just to ensure I have a good ground for the Headlights/turnsignals.

04-01-2025, 04:41 PM	#1
David in San Antonio Senior Member Join Date: Sep 2022 Location: San Antonio Texas Posts: 545	Roadster Disconnect with 2 Ground Wires How do I install a disconnect switch in a Roadster with two ground straps - one to the frame, the other to a transmission bolt? I need to understand both the wiring and how to mount the switch. This may seem obvious to many of you, but I’m starting my Model A education from scratch. Thanks in advance. __________________ David in San Antonio Late ‘30 Deluxe "Wretched Roadster" Alamo A’s Club

04-01-2025, 05:01 PM	#2
Y-Blockhead Senior Member Join Date: Jul 2011 Location: Redondo Beach, CA Posts: 6,642	Re: Roadster Disconnect with 2 Ground Wires Sponsored Links (Register now to hide all advertisements) David, connect the disconnect swith between the battery + side, if positive ground, and the frame. Connect the second ground from the where the first ground is bolted to the frame to the transmission. There are several places to mount the switch. Mount it so it is convenient to you. I mounted mine in my Town Sedan just in front of the front seat. I have a third smaller gauge wire running rom the frame to the headlight bar, just to ensure I have a good ground for the Headlights/turnsignals. Last edited by Y-Blockhead; 04-01-2025 at 05:08 PM.