I have some Dolphin gauges not yet installed and the correct 12V sending units. I am also going to install an EZ wire 21 harness in my '54 f100. My question is this: Since the EZ wire 21 has a fuse block, would I still need the '56 12V headlight switch? Thanks for any info you guys can send my way.

 

Are you converting the entire electrical system to 12V? Are you asking about the headlight switch because it is from the original 6V system, and you're not sure if it will work with 12V? Is there anything else you should tell us, for us to give you a more complete answer? I'm not exactly sure where you're going here.

 

Most everything is converted to 12V system. The headlight switch is 6V. Converting the whole thing to 12V. I'm asking do I need to have the 12V switch? Maybe I don't understand exactly what the light switch is...I thought it acted in place of a fuse box.

 

Because of the simplicity of early wiring systems, fuses were commonly placed in line or at switches for particular circuits drawing heavy loads, and not centrally located as is found on newer cars. Since you are rewiring your truck with a modern style fuse block, it isn't necessary to use a switch with an integrated fuse, although it won't hurt anything, either. Running 6 or 12 volts doesn't matter to the switch. It only opens and closes a circuit. What does matter is the amperage going through it. You can use the original switch, if you're sure it is in good condition. But you may want to consider a headlight relay to take the load off of going through the switch, if your new system doesn't have one built in, already. But with everything else new, I'd use a new switch, either the 54 model, or the 56, whichever you want to use.

 

Thanks. Thats what I needed to know. I appreciate your knowledge on this subject. I am so electrically ignorant when it comes to automotive wiring.

 

read this post by AxRacer, really a good description auto wiring..
https://www.ford-trucks.com/forums/3...ml#post2490395

sam

 

Please allow me to offer a small correction.

If you are converting to 12 volt negative ground, you will need the 56 headlight switch.

With the fuse block in the EZ wire kit you will have the protection you need for your powered items.

Having redundand protection via the headlight switch will be irrelevant since you are not distributing power off the headlight switch as in the OEM application, but rather the fuse block.

1951 to 1955 Headlight switches were configured specifically for 6 volts (1950 and prior are generic). 1956 and newer are all 12 volt.

You need the 56 switch because the rheostat that controls the intensity of the dash lights will not work on a 12 volt system with a switch that is configured for 6 volts (pre 56).

Here is the wiring schematic for the 56 headlight switch:

 

The EZ wire kit makes this easy - you get a guage power feed and a guage lights wire (seperate in the pack). Just study the wiring diagrams in the Ez instructions and those that come with the 12v switch. I'm totally new to wiring but have found it fairly straightforward.

 

Wiring is EASY. Just connect the dots!

 

Thanks everyone. I plan on getting the wiring started and next time I have consecutive days off. Those that have used the EZ 21, about how long did it take you?(taking the old wire out and installing the new harness) Julie thanks for the switch diagram. Axracer's explanation of the water flow idea makes good sense to me.

 

My EZWire 21 circuit install took about a days worth of time.
I had no harness prior.
deciding where to put the fusebox and then the couple wires to move between harness bundles, and then routing take the first few hours..

I soldered and heat shrinked every connection.

Sam

 

When installing a new wiring harness don't forget to install good ground wires between the battery, block, frame, cab, and bed. Make them or buy them. Do they still sell the flat, braided ground wires? Anyone !!!! chuck

 

They do sell those braded straps. Auto Zone has them and so does NAPA. They come in the smaller type (about 1/2 inch wide by 16 inches, or 1 1/4 inch wide in various lengths between 12 inches and 24 inches.

I used battery cables to run the grounds between the engine, frame, and battery then the braded hoses from bed to frame, cab to frame and front tilt hood to frame.

 

I wasn't aware that the 56 came with a 6 volt setup, all 4 of the 56's I've had have been 12 volt.

 

It didn't - 56 was always 12 volt. Did I miss something?