Kevin McNulty
Former Editor, Mud Life
If pack rats, electrical shorts, and decades of harsh weather have taken their toll on your rig's electrical system, or if you're looking to upgrade due to an engine swap, then you are in luck. We've compiled a list of manufacturers that can supply you with the right parts and help you get the job done.
Most replacement engine and chassis wiring harnesses are color-coded to match OEM wiring, or each wire is individually tagged for easy installation. It's important to use the proper tools: a good set of wire strippers and cutters, a soldering iron, a heat gun, shrink wrap, and quality connectors. If you do the job right, your new electrical system and rig will give you years of dependable service.
GM StandAlone Harness
Custom Jeep wiring harnesses are available from Current Performance. The harnesses are built to order for GM LT, LS, and '96-up Vortec engines. Current can modify an existing wiring harness to a standalone system, or build a complete harness to fit the engine swapper's needs. The kits include relays for a starter, fuel pump, electric fans, and A/C compressor. It has 12 circuits, 8 circuits for the end user (2 constant hot and 6 ignition feeds). These can feed the power to things like injectors, coil, engine computer, MAF/O2 sensors. Information: Current Performance Wiring, 727.862.1921, www.urrentperformance.com
Chevy & GM Harness
Power Plus 13 and 20 Series wiring kits are designed to offer an economical and convenient wiring solution for Chevy and GMC trucks by using an integrated, prewired fuse box and disconnects along the harness. By eliminating the disconnects and subharness assemblies and implementing the switches, fuse panel, and end locations, these kits offer streamlined installation. The Power Plus 13 and 20 include a new headlight and floor-mounted dimmer switch. Information: American Autowire, 856.933.0801, www.americanautowire.com
Easy Bronco Harness
Painless Performance has redesigned the Early Bronco chassis harness and the new 20-circuit, fully weatherproof harness and includes a composite glove box liner and fuse block mount for easy, convenient mounting and access to fuses. The wiring harness is 100 percent Ford color-coded and includes heat shrink weatherproof crimp connectors for all connections. There are nine fused accessory circuits for such add-ons as CB radios, GPS units, and driving lights. Installation is easy with a full-color 80-page installation manual, and the harness is available with or without new OEM headlight, ignition, wiper, and dimmer switches. Information: Painless Performance Products, 800.423.9696, www.painlessperformance.com
4.0L Jeep Conversion
Here is a cost-effective approach to swapping a modern fuel-injected engine into any vehicle. This custom subharness plugs into a factory 4.0L engine harness and provides OEM drivability and dependability. This conversion only requires a four-wire hookup to get the engine and transmission running. Other factory systems from Chrysler, GM, or Ford can be modified in a similar manner. Information: Hotwire Auto, 479.243.9115, www.hotwireauto.com
Early Bronco Wiring
This harness is a replacement for '66-'77 Ford Broncos that are still in factory condition or only slightly modified. The harness uses new Ford switches including the headlamp, dimmer, and wipers and has high-temperature labeled wire. New Ford connectors are used to fit the stock electrical devices, and special waterproof connectors are provided at critical spots for long-term reliability off road. The Centech fuse panel fits inside your stock glove box and uses 11 modern plastic automotive fuses in place of the old glass fuses. The harnesses are available with modern or factory Bronco ignition switches. Information: Centech Inc., 610.754.0720, www.centechwire.com
Fuel Injection Electrical
Howell's fuel injection harness allow the conversions of production GM V-8 and 4.3L V-6 engines into precomputer vehicles. Two styles of harnesses are available for the 454ci big-block, small block, and V-6. The systems include emissions connectors to match '87-'95 pickup truck and van engines. These harnesses require a vehicle speed sensor and a park and neutral switch (or manual transmission PROM) to be 50-state legal. The harnesses utilize '87-'95 pickup truck ECMs for proper function. Information: Howell Engine Developments, 810.765.5100, howellefi.com
High-Tech Powercell
The ISIS Intelligent Multiplexed System Power-cell is available for a number of vehicles and features a waterproof con-struction and a user level of programmability. Just plug in the power cables and hook them up to your loads, and the system tests itself to make sure all components are working. There are up to 25 different inputs on the Mastercell input unit (multiple inputs can control a single output) to up to 10 fuse-protected outputs on the control unit. Each output is rated at 25 amps. A single Mastercell input unit can control up to five power control units with up to 50 outputs. Additional Powercell control units and remotes are sold separately. All mating electrical connections use top-of-the-line Delphi Packard sealed connectors. Information: Littelfuse Inc., 847.824.1188, www.isispower.com
Jeep CJ Replacement Harnesses
Centech offers replacement harnesses for '76-'83 Jeep CJ-5s and CJ-7s. They are designed with standard CJ wiring, with additional construction given to critical connectors to ensure reliable off-road operation. A specially designed and sealed firewall connector maintains electrical integrity. Each harness includes a modern 28-circuit fuse panel using modern plastic fuses to allow for extra power where needed, and each Jeep harness easily mates to the stock dash switches and gauges. The engine wiring is universal to allow for engine swaps and V-8 conversions. Conversion to a GM engine is easy since HEI and GM alternator wiring is also available. Information: Centech Inc., 610.754.0720, www.centechwire.com
Universal Harness
The Builder 19 uses a compact ATO-style fuse panel that is fully encased in a closed box assembly with two mounting pads and has a fuse cover identifying all circuits by description and fuse rating. This is a good system for off-road applications. All high-amperage output circuits incorporate spring steel reinforced terminals. The forward lamp, engine, and rear body leads are all extra-long for special routing when a custom installation is needed. The Builder 19 includes: ignition, floor dimmer, and headlight switches; GM steering column connectors; horn relay and flasher units; and color instructions and schematics. Information: American Autowire, 856.933.0801, www.americanautowire.com
Connectors & Wire
If you're into building your own harnesses or making electrical repairs, PICO manufactures just about everything you need, including some replacement factory connectors. Crimp and heat-shrink and seal butt connectors provide a waterproof wire connection that's great off road. Crimp, solder, and heat-seal butt connectors are also available, which have a ring of low temperature solder around the barrel. The barrel has a window or divot in it. When heat is applied to solder, it flows down into the opening, soldering the connection. Cross-linked primary wire provides a higher temperature rating for use in enclosed engine compartments, and better resistance to abrasion compared to PVC-insulated wire. Information: PICO Wiring, 541.688.9646, www.picowiring.com
Easy-Access Fuse Block
The Access fuse block uses a fuse box with a removable magnetic mounting base for easy access, and the wire bundle lets you pull the panel out 18 inches. All wires are preinstalled. It has 24 fuses and seven relays, with an LED-ready flasher system. Four select-a-circuit fuse slots allow you to power your accessories by fuse position (constant battery power or only by ignition). Each harness is tailored to the specific truck and accessories to ensure plug-in compatibility. Information: Ron Francis Wiring, 800.292.1940, www.ronfrancis.com
18-Circuit Off-Road Harness
Take the time and hassle out of installing a new electrical system in almost any vehicle with a Summit universal wiring harness. The 18-circuit harness provides simple, plug-in hookup of your ignition coil, wipers, gauge and dash instruments, emergency flashers, electric fan, A/C, heat, headlights, radio (constant and ignition hot), turn signals, horn, dome light, brake lights, electric fuel pump, cigarette lighter, power windows, backup lights/cruise control, and power door locks. The harness is available with or without a GM column harness. Information: Summit Racing, 800.230.3030, www.summitracing.com
