Fuse panel help for 48 Willys

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1kzwoman

Minister of Fire
Dec 27, 2013
558
West near Yellowstone
I have the 48 Cj2A that has one fuse in the entire jeep..on the headlight switch. I would like to add a few more to protect the new wiring and the old jeep as well. Keeping it 6volt with generator.
Has anyone done this? I think 6 circuits would do it, but I don't know much about using relays. It seems they are a good idea since the ignition is used to kill all power.
Thank you for any suggestions in advance
 
Yes, this is a wonderful idea. Running all that power (unfused) through the ignition switch is a no-no by todays standards.
You'll now use the ignition switch to trigger the relays, which requires far less current passing through the ignition switch.

I don't have a lot of experience with 6V systems, but there are a number of premade fuse/relay panels available through the automotive aftermarket and I'm sure somebody out there is making things dedicated to 6V users. (check out painless wiring, ron francis, maybe there is a willlys-resto supplier?) Usually these kits come with extra long pigtails that are even pre-printed on the wires to indicate which circuit they correspond to; then you cut to length and solder on your existing plugs/bulb sockets. It is by no means a fun project, but the results are quite rewarding.

I can't positively say if standard automotive relays (12V) would operate the electromagnetic coil properly at 6V, but it may be worth a shot if you're looking to DIY a harness. Typically these relays are made to handle ~30A max load, so you're looking at a relay for the headlamp circuit, and probably a couple more relayed power circuits to cover other power needs (lighting, wipers, radio, hvac fan)

Biggest thing I've noticed when re-wiring older vehicles with modern fuse panels and new harnesses, is how much brighter the lighting is. Those old wiring harnesses slowly become giant resistors as they break down. This also gives you an opportunity to evaluate your ground connections, and clean/add ground points as needed.
 
The Willy has headlights, one taillight, two park lights, one wiper, two heater fans. Natural AC , no radio, .
The heater fans, and cloth top are seldom used. But all work!
I have upgraded and cleaned grounds underwood and plan to continue through out as new harness is on order,
I'm replacing electical switches too.
The harness will be OEM style as Willy is OEM for most part , I use NOS parts when I can find them.
The generator is 35 amp, with separate voltage regulator.
 
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I'm thinking the installation of a fuse panel near the dash mounted ignition switch is the easiest spot. The starter is a floor mounted switch.
Can I safely use 12 volt fuses with correct amperage based on wire size? Relays for H/L headlights, and horn any other suggested spots?
Again wiper and heaters are seldom used but work
 
The Willy has headlights, one taillight, two park lights, one wiper, two heater fans. Natural AC , no radio, .
The heater fans, and cloth top are seldom used. But all work!
I have upgraded and cleaned grounds underwood and plan to continue through out as new harness is on order,
I'm replacing electical switches too.
The harness will be OEM style as Willy is OEM for most part , I use NOS parts when I can find them.
The generator is 35 amp, with separate voltage regulator.
Why are you keeping it 6 volt?
 
Why are you keeping it 6 volt?
Because it is period correct , same as all other items (except for battery and fuses) and it's worked for 70 years (nearly) .
It's never going to go out of the family and the 12v upgrade is pointless in our use for the vehicle. Teaching basic mechanics, driving as a kid, building memories, telling stories of the jeep with great great grandfather elk in the back.
 
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Can I safely use 12 volt fuses

Yes, voltage rating of a fuse is based on the physical size of a fuse. The gap that is created when the fuse opens needs to be large enough to prevent an arc from jumping across the gap and recreating the circuit.


with correct amperage based on wire size?

This would be wrong, it offers no protection the the device being fused, only protects the wires and the output of the generator/voltage regulator. The fuse size is based on the device placing the load on the curcuit not the ability of the wire to feed the curcuit, you'll need to either calculate the loads or measure them with an ampmeter, (not the best method) then include a "cushion" in the fuse size to allow for the inevitable spike in power draw when the device is powered on. Electric motors have a currrent spike at startup but while running draw less curent.

Measuring load with an amp meter really should be avoided, for example, the wiper motor will draw more current at different times, snow, rain and wind could easily require more power, a heater fan with the inevitable leaves and debris in the fan housing will effect the load too.

Another thing i'd keep in mind while wiring, since a vehicle will be moving there are vibrations and shaking that the wires will be subjected to, soldering creats a stiff spot and needs to have room to flex. The joints where splices are made should have attention too, moisture will wick it's way into the connection and corrode over time. There are heat shrink tubes available with sealer inside for truely water proofing connection. For your project, look at what was done 70+ years ago, you'll see what has stood the test of time.

6 volt relays are readily available.

The widsheild wiper is electric? Would have expected it to be vacume.

Enjoy the project, sounds like fun.
 
Yes, voltage rating of a fuse is based on the physical size of a fuse. The gap that is created when the fuse opens needs to be large enough to prevent an arc from jumping across the gap and recreating the circuit.




This would be wrong, it offers no protection the the device being fused, only protects the wires and the output of the generator/voltage regulator. The fuse size is based on the device placing the load on the curcuit not the ability of the wire to feed the curcuit, you'll need to either calculate the loads or measure them with an ampmeter, (not the best method) then include a "cushion" in the fuse size to allow for the inevitable spike in power draw when the device is powered on. Electric motors have a currrent spike at startup but while running draw less curent.

Measuring load with an amp meter really should be avoided, for example, the wiper motor will draw more current at different times, snow, rain and wind could easily require more power, a heater fan with the inevitable leaves and debris in the fan housing will effect the load too.

Another thing i'd keep in mind while wiring, since a vehicle will be moving there are vibrations and shaking that the wires will be subjected to, soldering creats a stiff spot and needs to have room to flex. The joints where splices are made should have attention too, moisture will wick it's way into the connection and corrode over time. There are heat shrink tubes available with sealer inside for truely water proofing connection. For your project, look at what was done 70+ years ago, you'll see what has stood the test of time.

6 volt relays are readily available.

The widsheild wiper is electric? Would have expected it to be vacume.

Enjoy the project, sounds like fun.

Yup you're right on , thank you for reminder. Love this forum's helpful members.
Vacuum wiper was OEM, Bosch 6 volt was period correct upgrade. Vacuum ports are plugged at this time. Vacuum driven wipers are still available.
 
Because it is period correct , same as all other items (except for battery and fuses) and it's worked for 70 years (nearly) .
It's never going to go out of the family and the 12v upgrade is pointless in our use for the vehicle. Teaching basic mechanics, driving as a kid, building memories, telling stories of the jeep with great great grandfather elk in the back.
Oh I didn't think you were worried about period correct. Sorry.
 
Oh I didn't think you were worried about period correct. Sorry.
I'm not a purist about the period correct or I wouldn't have done the red top optima or consider a fused set up. It's a decision made, simply because the jeep is so close to original.

It is an early 48 with 15xxxx serial number & body matching,motor is original too. I'm doing as close to period as possible, before it becomes impossible to get parts. Drag link is impossible already.There were several changes in CJ2A at serial number 17xxxx mid year in 48.

No apologies necessary! I discussed 12v upgrade with my 37 year old son...he won because of what I have told you.
 
Doesn't fusing, adding relays, electric wipers alter the periodicity? Not that I'm against these changes, they are all good ideas, but it seems to dilute your son's purist pov.
 
Doesn't fusing, adding relays, electric wipers alter the periodicity? Not that I'm against these changes, they are all good ideas, but it seems to dilute your son's purist pov.
Thank you for your interest!
The electric wiper is a 6 volt through the windshield frame option added by OO on the drivers side, passenger side is hand operated. The passenger seat ,rear seat, heater are accessories purchased with the jeep. The generator splash shield, heat shield under master cylinder are also.
Having Willy as it has been all of my 56 years, and all of his 36 years for his son is what my son wants. I took him out to the shop and had to show him how brittle and frayed some areas of wire are before he agreed to install new braided wire.
The fusing and relays I am researching, simply because it's easier to do when I install the new wiring harness.
His stance ( I'm sure)is going to be if we do the install properly it will be good for another 70 years. He will argue that it's stored inside and only driven in summer now.

You are correct it would not be a period correct option.

I am not required to even add seat belts, turn signals or a second brake light in my state.
I tried to talk for those mods as well, my son said if he had to haul it to the moutain to use it he would, then asked me to "Keep it Grandpa's Jeep"

Some people choose or purchased a CJ2A that has been so heavily modified or neglected they no longer resemble what they were when built. People buy body tags, run motors without oil filters, install V8 short block motors.
Other people would buy rusty CJ2A's to restore by replacing body tubs, (still others buy NOS paint for only NOS or OEM restored jeeps wish we could afford that)
As you said I am not against them doing it , but it's not what we have or want.
Before someone comments on my grandson riding in the jeep without a car seat he didn't at highway speed on paved roads we took second vehicle to base of trail.
 
Well, I'm with you. If it makes it safer without radical change then bring on the fuses. I would also be replacing most rubber parts, starting with the brake system components including hoses.
 
Well, I'm with you. If it makes it safer without radical change then bring on the fuses. I would also be replacing most rubber parts, starting with the brake system components including hoses.
Brake hoses, lines, drums, shoes hardware,master cylinder, wheel cylinder parts are here already.But looks like bleed and adjust is all that is needed at this point. Thank you for the suggestion however.
 
Be green I have wheel bearing and races ,seals as well. Been through fuel system as well. It's parked for winter repair after the test drive for Christmas trees even if it was excellent. Ross steering and tierods are first did bell crank and drag link repair already. Then steering knuckles seals.
Then pulling front and rear differential covers to inspect.
They are common parts for many model years so I am not concerned about their availability in the near future.
 
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