The Ford Barn

2002p51 · 07-27-2010, 07:06 AM

We started re-wiring our '47 Mercury yesterday (converting it to 12 volts), and in the process of ripping out all the old wiring, I came across this:

It was way up under the dash. It has a small "Ford" script on one side. Since I'd already pulled out all of the under hood wires I couldn't trace where it was connected.

So, anybody know what this is?

41ford1 · 07-27-2010, 07:19 AM

Lighting circuit breaker and ignition ballast resistor.

Terry,OH · 07-27-2010, 07:25 AM

there are two devices on the fiber board. The small round one is the voltage dropping resistor for the ignition coil. The original coil does not run on 6v more like 3.5V
The square device is the light circuit breaker. if the current in the light circuit is excessive (like due to a short circuit) it operates and removes the voltage to the lights, after it cools it automatically resets and returns the voltage, if the overload is still there it will operate again. If your going to 12V you will want to replace the circuit breaker with fuses, if you plan to use a 12V coil the resistor is also unnecessary. If your going to use a coil that requires a series dropping resistor the original one on this board is not the correct size.

2002p51 · 07-27-2010, 07:56 AM

Sponsored Links (Register now to hide all advertisements)

Thanks guys,

I'm using a complete kit from American Autowire so I'll be replacing everything with new parts from the kit.

07-27-2010, 07:06 AM	#1
2002p51 Junior Member Join Date: May 2010 Location: Kingsport, TN Posts: 22	What the heck is this thing? We started re-wiring our '47 Mercury yesterday (converting it to 12 volts), and in the process of ripping out all the old wiring, I came across this: It was way up under the dash. It has a small "Ford" script on one side. Since I'd already pulled out all of the under hood wires I couldn't trace where it was connected. So, anybody know what this is?

07-27-2010, 07:19 AM	#2
41ford1 Senior Member Join Date: May 2010 Location: ManchVegas, New Hampshah Posts: 1,589	Re: What the heck is this thing? Lighting circuit breaker and ignition ballast resistor.

07-27-2010, 07:25 AM	#3
Terry,OH Senior Member Join Date: May 2010 Posts: 4,751	Re: What the heck is this thing? there are two devices on the fiber board. The small round one is the voltage dropping resistor for the ignition coil. The original coil does not run on 6v more like 3.5V The square device is the light circuit breaker. if the current in the light circuit is excessive (like due to a short circuit) it operates and removes the voltage to the lights, after it cools it automatically resets and returns the voltage, if the overload is still there it will operate again. If your going to 12V you will want to replace the circuit breaker with fuses, if you plan to use a 12V coil the resistor is also unnecessary. If your going to use a coil that requires a series dropping resistor the original one on this board is not the correct size.

07-27-2010, 07:56 AM	#4
2002p51 Junior Member Join Date: May 2010 Location: Kingsport, TN Posts: 22	Re: What the heck is this thing? Sponsored Links (Register now to hide all advertisements) Thanks guys, I'm using a complete kit from American Autowire so I'll be replacing everything with new parts from the kit.