Wire Harness Foolproof Upgrade

How many times have you worked on your Mopar, only to find out that the original wire harness had either A) been butchered by a previous owner, B) has the insulation peeling off, causing a short, or C) the bulk head connector has corroded and is causing a major problem? What if you're planning to update your Mopar to current 21st Century ideas?

When it comes to the wiring, Littelfuse is a company that you may not have ever thought about for your Mopar. But, for most of its history, the core business for Littelfuse was the protection of wiring circuits in automobiles. Littelfuse products are used in a lot of products that use electrical energy, including automobiles, computers, consumer electronics, handheld devices, industrial equipment, and telecom/datacom circuits. Over the past 10 years, Littelfuse has been providing circuit protection solutions to enhance vehicle safety and reliability, protect increasingly more sophisticated electronics and introduce new high-current technology into vehicles. Littelfuse already works with major automakers in North America, and it's a leading supplier to retail aftermarket outlets. Key products include blade fuses, bolt fuses, MasterFuse, TVS diodes, varistors, hybrid electric vehicle fuses, and cable protectors. But enough with the who they are stuff, what is this ISIS kit?

When Littelfuse, Inc. announced the end of wiring harness drudgery with the introduction of the ISIS Multiplex System--a solid-state electrical system that eliminates tangles of wire, slashes install time in half, and gives auto enthusiasts complete control over their cars' accessories--we were more than interested. The kit is the first multiplex system to make OEM technology available to any car, whether it be a street rod, resto-rod, off-roader, kit car, or muscle car.

ISIS wiring employs a plug-and-play modular-design identical to that used in OEM vehicles today. Multiplexing uses computerized power distribution to reduce the amount of wiring and to increase performance. The basis behind ISIS is as such; a builder begins by installing an ISIS Mastercell Input Unit behind the dashboard--or wherever he chooses. An ISIS Powercell Control Unit is then installed at a point near a cluster of electrical components. For example, one can be installed in the front-end of the car to handle lights, turn signals, horns, starter, etc, while a second is mounted in the trunk for rear turn signals, fuel pump and stereo components. Wiring each accessory takes four easy steps. First, connect the desired control switch to the Mastercell, and then connect the Powercell control-outputs to the load. Now, connect the Powercell to the battery, and then connect the Powercell to the Mastercell with the C.A.N. bus cable--that's it. When the switch on the dashboard is activated, the microcontroller in the Mastercell tells the Powercell to activate the appropriate circuit.

The ISIS System uses Mosfet switches in the Powercells for handling typical automotive loads of up to 25-amps per node. Each Powercell can handle up to 10 circuits, and up to five Powercells can be run by one Mastercell, for a total of 50 individual circuits per Mastercell. The electrical operations are almost endless.

Wiring is simplified, because wires from each electrical accessory need to run only to the Powercell Control Unit located nearby. Wiring the vehicle becomes dramatically easier because the wires for all accessories no longer run all the way from the switch and fuse box to individual accessories.

What if you have a problem with the ISIS kit, how do you find it? For quick diagnostics, an LED indicator is used on each output node that indicates at a glance whether the circuit has an open fuse, an open circuit, or is functioning normally. So all you have to do is look at the Powercell box for an LED, and it tells you what you need to know.