Electrical

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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.   

To accommodate the accessories not accounted for in the original wiring harness, I purchased a switch plate with LED lighted rocker switches.  This provided a compact switch panel for wipers, reverse light, front driving lights, brake line lock, a fan cutoff, and an extra auxiliary switch.  I mounted four standard automotive relays to the firewall near the fuse block to support the switches.

I cut a separate steel plate, to mount to the right of the steering column, to hold the headlight switch and the keyed ignition switch.  For the headlights, I didn't want to mount a standard dimmer switch to the floorboard due to lack of space and awkward placement with the non-standard pedals.  So I looked to Speedway Motors for another hotrod trick.  They sell a headlight pull switch with an extra detent built in to turn on the brights.  This is a clean and simple solution.  The keyed ignition switch came with the wiring harness and nestled right in beneath the headlight switch.  It's a tight fit, but it's organized and I like the overall look.

I wanted to install one modern convenience in the form of a power port and USB ports for charging electronics.  I found a nice part on eBay that includes a 12v power port and 2 USB ports with weatherproof rubber caps to keep the rain and dirt out when not in use.  This is a nice unit with a black finish that blends with the rest of the dash without ruining the vintage aesthetic.  

I had just enough room above the headlight/ignition plate to squeeze this unit into place.  Installation was a breeze too, as it simply required drilling two holes with the hole saw, and for once the plastic ports had threads long enough to work with the fiberglass dash.  

One note on working under the dash of a flatfender Jeep - you will not enjoy your time there!  It involves contortions over the body tub door lip, around the seats, and under the dash.  Because the dash cannot simply be unbolted and removed as on later CJs, there's really no alternative other than to man up and take the pain.

I covered the placement and installation of the gauges into a custom panel in the Body topic.  But it's worth a quick mention here in the electrical topic as well.  I used a combination of gauges from Sunpro and Autometer to include speedometer/odometer, fuel level, engine temperature, oil pressure, and voltmeter gauges mounted into the central dash plate.  I also added a tachometer mounted separately on the steering column.

Wiring for the gauges was very straightforward, and because of the central mounting in a single dash plate it was fairly compact, which is good due to the limited space.  It was still a challenge attempting to determine the correct length of the wires so that they could be tucked up out of the way in an organized fashion.  This had to be coordinated for not just the gauge wires, but also the auxiliary switches, the headlight and ignition plate, the power/USB unit, and the steering column wiring.

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.   To facilitate this, I mounted a Painless Wiring remote battery junction terminal kit to the firewall (see details below).

To secure the battery, I looked to eBay for a universal mount, steel dimple die box tray made specifically for a group 34 Optima battery.  This design is strong but light weight and came in bare steel.  I prepped and sprayed the tray in black semi-gloss before mounting it.   

For the battery itself, I selected an Optima YellowTop AGM (group 34) battery with 750 cold cranking amps (cca) and 120 minutes of reserve capacity @25 amps.  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.  

I chose the YellowTop (as opposed to the standard RedTop starting battery) because it's a true dual-use battery providing premium starting power and deep cycle capabilities.  This is useful for lengthy winching sessions or just powering the air compressor with the engine off, and I like the extra peace of mind it brings.  That peace of mind doesn't come cheap, but it's money well spent.

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.  It was easy to install longer carriage bolts for mounting.  

Needing a reverse light, I installed a single Hella Micro FF driving light that I had on hand to 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.

I knew that even with the upgraded Hella/BeamTech headlights, I would still want some additional lighting up front.  So I did some searching and decided on a set of AuxBeam 4" LED fog lights.  These lights have tough aluminum housings with cooling ribs and are IP68 rated for water and dust resistance.  They produce 3600 lumens and the 6500k temperature matches the color of the headlights.  They are also rated for over 50k hours of use.  

I mounted these on top of the front bumper on either side of the winch.  They utilize stainless steel adjustable mounting brackets and are engineered to be shock resistant, which should serve well in tough off-road environments.

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. 

I believe the original driver side wiper on the 1947 CJ-2A would have been vacuum driven, and the passenger side would have been manual.  Wanting to upgrade to more modern 12-volt wipers, I purchased two Omix-Ada wiper kits from Quadratec.com.   Each wiper motor has a manual switch on the housing, but I wanted to wire them together and route the on/off function to a switch on the dash.  This was easy enough to do, and makes actuating them more convenient.

One thing I found when lying the windshield flat on the hood is that the motor rod that sticks through the windshield frame was too long.  This required some careful measuring and deft cutting with a Dremel cutoff wheel, but once shortened, the wiper arms had plenty of clearance with the hood folded forward.