When it comes to the electrical system on an early CJ, especially compared to a modern vehicle, it's about as rudimentary as it gets. Even so, reliability and durability are top priorities given the remoteness of most trails, the constant vibration on and off-road, and the harsh environments to which the electrical components are subjected. The wiring harness, connections, gauges, and switches need to be high quality, solidly connected, and protected from damage.
One of the benefits of eight decades of Jeep CJ/Wrangler history and enthusiast support is that you can find nearly any component you might need. And if you can't, some enthusiast will identify and fill the gap. You can buy wiring kits from companies like Walcks 4Wheel Drive, KaiserWillys, and The Jeepster Man among others. While searching for a complete wiring harness, I found a small company (unfortunately no longer in business) offering vehicle-specific, made-to-order wiring harness kits using parts Made in the USA.
When placing the order I was able to specify the options on the CJ, such as turn signals, heater, towing pigtail, etc. to accommodate my specific vehicle. The kit arrived packaged in 4 separate sections: rear, dash, fuse block, and engine and a separate package of connectors and zip ties. Each section was correct length, pre-terminated, and wire loomed. The instructions were very thorough and included the sequence to follow during installation along with individual steps and clear wire mapping by color.
I decided to route the rear harness inside the body tub rather than along the frame rail for extra protection. I tied it to the tub with wire hangers on the driver side rear inner fender, and routed it under the the inner lip of the driver door on its way beneath the dash.
I mounted the fuse block under the dash on the passenger side firewall to keep it accessible and centrally located for the gauge cluster, rear harness, and engine harness. Due to the fiberglass body, I used multi-terminal grounding strips mounted strategically on the tub and tied into the frame. This required a bit of extra work and wiring, but will ensure plenty of effective grounding points for the components.
There are a few additions I needed to account for, such as the winch, auxiliary lights, an electrically actuated brake line lock, and CB radio, so there was some additional wiring to tie into the harnesses and fuse block. Overall this complete kit was an excellent foundation for the electrical system, and made wiring the Jeep much easier than piecing everything together from scratch.
With room under the hood at a premium, I decided to mount the battery remotely in the cargo area inside a lockable polymer storage box from Tractor Supply. In addition to the battery, I plan to install an onboard air kit next to the battery tray in the locked storage box. This necessitated a longer set of custom battery cables for the charging system and the winch, but installation and routing was straightforward.
For the battery itself, I selected an Optima Red Top AGM (group 34) battery with 800 cold cranking amps (cca). I've used Optima batteries for years in various vehicles and I've never been disappointed. Their primary benefits in an off-road oriented vehicle are extreme resistance to vibration, long life, maintenance free design, faster recharging, and the ability to be mounted in any position. To secure the Optima, I looked to eBay for a universal mount, steel dimple die box tray made specifically for the Optima Red Top. This design is strong but light weight and came in bare steel. I prepped and sprayed the box in black semi-gloss before mounting it.
As mentioned in the Engine and Body topics, I was very limited on space when it came to the engine fan. The original mechanical fan was just too close to the radiator, and I decided to go with an electric fan setup. Having already fabricated mounting brackets for the fan, I installed the brackets and fan to the grill.
The fan came with a temperature sensor calibrated to automatically turn on the fan at 180 degrees Fahrenheit, and I'm also wiring it to a dash switch so I can disable the fan manually for deep water crossings or really cold winter days.
For the lighting, I had some specific goals based on my personal preferences. For the taillights, I really like the retro look of the small round original lights. It would have been easier to install the later CJ taillights with integrated reverse lights and a license plate light, but I'm a sucker for the retro aesthetics. I originally purchased the OEM replacements from Omix-Ada, but again the fiberglass body interfered. The rear wall of the tub is much thicker than the steel body, and the integrated OEM mounting studs were too short. I paid a visit to the local Rural King and found the exact lights, but instead of integrated mounting studs, they utilized the removable carriage bolts for mounting. It was easy to install longer carriage bolts for mounting.
Needing a reverse light, I installed a single Hella Micro FF driving light on the rear bumper. It's compact enough to fit out of the way and bright enough to throw a ton of light where needed.
For the front marker lights/turn signals I really like the amber colored lenses from the CJ-3B, even though the CJ-2A came with clear lenses and amber bulbs. So I purchased a set of these from Omix-Ada and installed simple angle brackets to mount them to the grill in the stock location.
For the headlights, I was a bit torn - I really wanted the improved color and visibility of LEDs, but I wanted to retain the OEM look. I just don't think an ultra-modern LED bulb setup would look right on a flatfender. So I compromised and installed a set of Hella Vision Plus 7" housings with H4/9003 LED bulbs from BeamTech. These high-quality Hella housings look just like the original sealed beam headlights, but have a port in the back for mounting an H4 halogen bulb. The BeamTech LED bulbs are an exact-fit replacement for H4 halogens. The aluminum, fanless design runs cool, the LEDs draw a fraction of the power of halogen bulbs, and the 6500k temperature approximates daylight; they are also guaranteed for 30k hours of use. The combination of the modern internal Hella reflectors and the LED bulbs greatly exceed the output of standard halogens for the road or trail.
One of the challenges for my build is that I had to relocate the battery from the engine compartment to the cargo area. A second challenge was the fiberglass body which complicates grounding of simple components like lights and switches. To address each of these, I turned to Painless Performance for their remote battery junction terminal. This piece is made to mount through the firewall (or any other flat vehicle surface) and provides stout battery-type terminals on either side, one positive and one negative. Mounting this junction through the firewall on the passenger side of the tub solved several issues. The first is that it provided a convenient connection point for the wiring for the Superwinch EPi 9, preventing the need to run extra long cables all the way to the battery in back. Second, the positive terminal on the firewall under the hood will make for a simple alternator hookup since the battery is remote. Lastly, I mounted a terminal block under the dash next to the negative terminal which will serve as a convenient grounding site for the dash mounted switches and such.