Anybody build there own?

[MikeS]

Looking at the wiring diagram it doesn't seem like there is a lot to building your own harness from scratch. I was just wondering if anyone had built there own and had any tips? Wire sizes , etc.

[oldtime]

I build all my own harnesses.
I bind (wrap) them with electrical tape like the originals were
It's very easy.
Especially easy true If you have an original one to copy.

Here is a post that may be of some help it provides correct detail for building a post 1956 (cluster gauge) wiring harness.

I have built early type harnesses (individual instrumentation) but none with the cloth covered wires.
.

[squidtone]

I just did this completely from scratch. While the simplest thing would be to replicate the original system, it's hard not to be tempted to perform some upgrades. Do you want to keep it 6V, include some fuses, add a passenger side light, turn signals, etc?

In my case, I went 12V alternator conversion, added relays and fuses way up under the dash (hidden) and a Ford style starter relay. but I re-used the original switches, light sockets and starter "stomp" switch. I used modern PVC jacketed wire which can be covered with black harness tape. So while some of it is obvious, it's subtle enough to not be glaring.

I'd definitely do it again. I found it satisfying to do myself.

Good luck!
 PS if you'd like, I can post my schematic for a "modern" style system if you are going to lean that way.

[64CJ5]

Made my own.  Used different colors for different circuits.
Copied my 64 CJ5 wiring, but do not have directional or heater circuits  I deleted the Ford alternator as it had bad bearings and put in a one wire GM alternator.  My M-38 has a 1976 2.3L Pinto engine.

[PercyUK]

Hi, I also made my own as I thought the price of a new one was quite a lot for a few lengths of wire.
I used online research to identify how to calculate the correct thickness of each wire required, used black expanding conduit to run it through and short lengths of heats shrink at each end to keep it nice and tidy.
I did want the original style conduit but could not get hold of it easily here.
I was not happy about having one big fuse for the whole vehicle (I have upgraded to 12v) so put a fuse box under the dash with a fuse for each line such as lights, brakes, headlamps etc.
Whilst I was there I replaced my headlamps with halogen bulb replacements that had the side light enclosed within. I then made the original side lights into indicators by fitting amber bulbs so from the front you would not know that anything has changed.
Good luck

[squidtone]

Hey I made up a schematic using Digikey's online, in-browser schematic tool. It's a little clunky to use, but with some cheating on how to layer text and blocks, it sort of conveys my 12V CJ3A system. I'm attaching it as a PDF file.
Link to the schematic at Digikey:
https://www.digikey.com/schemeit/project/ff50-LPDABA0302CG/

[MikeS]

What about wire sizes? 12ga, 14ga? Hard to tell what the cloth covered stuff was.

[elawson]

I've made all of my own harnesses.....on the vehicle and wrap it as I go.  My 3A was 6 volt when I wired it (later converted it to 12V) so I went with heavier wire than usual.

I used 00 gauge wire for the battery cables to the starter and ground. I tied the fat ground wire to the starter (the bolt at the back end of the starter (towards the front of the Jeep) that holds the starter to the engine block and then ran a 10 gauge ground wire from there to the Jeep frame. It's not standard, but it sure makes the starter work much better.


10 gauge for the generator armature to the regulator, from the regulator to battery (very likely the starter + terminal) and to the fuse block. Also, think about the protection of any of the 10 gauge wires connecting to the battery or starter + terminal.  Usually this will be a few inches of 14 gauge fusible link wire  There is no sense in making the Jeep with wiring problems into a road flare.

12 gauge wiring for the headlight stuff,

14 gauge wiring for everything else.

I was trying to keep the voltage drops to a minimum in a 6 volt system.  If one is 4 times as careful when compared to a 12 volt system, the 6 volt system will work equally well.  When my '3A was still 6 volts, the lights were so bright that if I forgot, oncoming drivers would have to remind me to put my lights on low beam.  And, the engine cranking speed was just like the 12 volt CJ5s.

I know the dash light and high beam indicator lights could be smaller wire, but these wires are usually protected by the same circuit breaker as the headlights and I didn't want to get wires so small that an "almost short circuit" in the indicator wiring would pull enough current to damage the wire, but not trip the breaker.

My reason for using a circuit breaker in the headlight system is that it would automatically reset after an overload....

One other thing is that I used waterproof splices--even where it wasn't likely to be expected to get wet.  I asked the guy along the road if I could get my Jeep across the puddle in the middle of the road and he said yes...I drove across and got my seat wet....The guy said he was surprised about my problem as he had seen some ducks walk right across the puddle with no problem....... :-)



That's how I did my CJ3A in the late 1980s and it's been working perfectly.

[Dutch_Jeeper]

"I used 00 gauge wire for the battery cables to the starter and ground. I tied the fat ground wire to the starter (the bolt at the back end of the starter (towards the front of the Jeep) that holds the starter to the engine block and then ran a 10 gauge ground wire from there to the Jeep frame. It's not standard, but it sure makes the starter work much better."

Good advice

One of the easiest and best mods for your starter and the first thing you should try if you are having issues with it, solves it 9 out of 10 times