The ISIS 3-Cell starter kit...
The ISIS 3-Cell starter kit is capable of handling 20 circuits with the ability to control any electrical function, more than enough for the typical classic Ford or late-model Ford retrofit. We hope to get more acquainted with the 3-Cell system when we install one in our Project Generation Gap later in the year.
Whether you’re restoring a classic Mustang, building a restomod full of modern technology, or assembling a Factory Five Roadster, you’ll have to make some important decisions about the wiring in your project. Wiring can be one of the most complicated jobs encountered during the course of an automotive restoration or custom build. It requires the careful routing of numerous control wires and power leads to and from switches, and the various other electrical components within the chassis and body. The wires are bundled into cables that must be carefully hidden to achieve a clean and sanitary looking installation. On a restoration project, sometimes the factory harness will be serviceable and sometimes it will not, while those starting from scratch are doing just that. Before you go forward with the electrical aspect of your next project, you should be aware that a new choice for vehicle wiring exists in the form of the Littelfuse ISIS Intelligent Multiplex Wiring System. The ISIS arrangement is a modular micro-controller–based automobile electrical system than can replace or augment a conventional wiring harness. It uses a centralized command or “hub-and-spoke” arrangement to greatly simplify electrical wiring projects.
Before we examine the streamlined...
Before we examine the streamlined ISIS components, let’s take a gander at what we’re trying to replace. Looking at this mess of overheated and spliced wires from a late-model Mustang (and this is just the dash wiring) it’s easy to understand how the ISIS system might simplify and sanitize a new wiring installation. Replacing or refurbishing a wiring harness like this one could be a can of worms when compared to an ISIS installation, which uses two or three single-block units to control the whole car.
Rather than having a complete and separate circuit for each and every vehicle electrical function, such as headlights or turn signals, the ISIS system uses a Mastercell input unit that communicates to a remotely located Powercell through a single small connection. Electrical switches in the car are wired directly to the Mastercell unit. These switches are all ground side controlled and carry low-current only. When a switch is activated the input is transmitted from the Mastercell to the Powercell via a CANBUS connection. The Powercell then executes whatever command the Mastercell provides. A typical car installation might have two Powercells, one for each end of the car. However, the Mastercell can command as many as five Powercells, each with ten possible fused outputs, for a total of 50 functions that can be controlled by a single Mastercell. This capability is very useful for large vehicles with numerous requirements such as a motorhome or a boat. Let’s have a look at the individual components of the ISIS system and see just what the potential advantages are.
Besides simplicity, one of the big advantages of the ISIS system is ease of installation. The wiring of a vehicle can be a big part of the project and can take many hours to complete. However, with the new ISIS system you can cut that time dramatically and you don’t need to have a lot of past wiring experience to complete a clean installation. As well as ease of installation, enthusiasts will appreciate the approximately 40 percent weight savings realized using the ISIS arrangement. Another advantage is safety. As we just mentioned, the low-voltage and low-current design for switching and controlling electrical functions eliminates high-current wiring under the dashboard. This reduces the possibility of an under-dash electrical fire or overloading a dash switch. All inputs are ground-switched, further simplifying the electrical system. A low-current dash harness is available as an option, providing easy connection to all switches and gauge wiring.
This project was a perfect...
This project was a perfect candidate for a complete rewiring. One look in the engine bay tells us that a sanitary electrical installation was near the top of the list. This Mustang fastback exhibit at the 2008 SEMA show was built by Bare Speed out of Sunnyvale, California. It features ISIS wiring throughout. The ISIS system uses fewer wires, allowing more interesting routing options for higher-end show cars or even if you just want to clean up your weekend toy’s engine compartment.
A close-up of the ISIS Mastercell...
A close-up of the ISIS Mastercell shows the weather-proof enclosure, which is sealed with watertight gaskets for maximum protection. All enclosures feature clear covers for easy system status checks. All plastics used in the construction of the enclosures are UL 94V0. Bases are glass-reinforced, high-temperature nylon for strength and temperature resistance, while the covers are made of high-temperature polycarbonate. A single Mastercell input unit can control up to five Powercell control units for a total of up to 50 functions. All mating electrical interfaces use top-of-the-line Delphi Packard sealed connectors.
Here’s the Powercell installation...
Here’s the Powercell installation on the fastback show car. Although the ISIS components are tightly sealed we wouldn’t want to have the units exposed to the weather directly, and it’s doubtful if this radical rig will see much wet weather road time. It’s plain to see that the wiring complexities on this project have been reduced to a minimum using the ISIS Mastercell as the brains of the operation.