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.
Here’s a close-up shot of...
Here’s a close-up shot of the ISIS Powercell. It features the same rugged construction as the Mastercell and is tightly sealed against contaminants. The Powercell control unit is rated to operate in an environment up to 125 degrees (Centigrade). As with the Mastercell unit, the plastics used in the enclosures are UL 94V0 with bases of glass-reinforced nylon.
With the ISIS system, things like intermittent wipers, self-canceling turn signals, timers, soft start functions (turning the headlights on at 50 percent pulse width modulated voltage for 500 milliseconds before giving them full voltage for example), and more are all easily handled by ISIS. Custom programming is available from ISIS directly if you’ve got something to control that’s not pre-programmed, and by the time you read this, its inCODE programmer will be available, allowing you to program your own ISIS hardware at home, via computer. Simply make changes to your Mastercell programming and download it instantly from your computer into your Mastercell—perfect for future electronics upgrades.
Here’s a more conventional...
Here’s a more conventional Mastercell installation in a classic Mustang, underneath the dash and directly above the transmission tunnel. This is a much better installation for a car that’s going to be daily driven. The Mastercell input unit is rated up to an 85-degree (Centigrade) environment. You can also see the front Powercell adjacent to the Mastercell.
The ISIS Multiplex Systems are also competitively priced when compared to a conventional direct replacement aftermarket harness. The ISIS 2-Cell Starter Kit will handle up to 10 circuits and lists for $799. The 3-Cell kit controls up to 20 circuits and goes for $999. Additional Powercell control units cost $349 each. The optional inDASH dash harness costs $159.
From where we sit, this new ISIS Multiplexing Wiring System looks like a big step forward for those faced with the wiring challenges found on major projects with increasingly complex electrical demands.
Here’s a typical rear Powercell...
Here’s a typical rear Powercell installation. This unit is set up in the trunk to control the rear electrical demands of this project. You’re looking at the whole shooting match with all taillights, brake lights, turn signals, and license plate lamp, plus the fuel pump, wired into the Powercell. Commands from the Mastercell come in one end of the box and the result goes out the other end. It’s that simple. After situating your master and power cells just plug in the power cables and complete the connections to the loads. Once the installation is complete the system tests itself to make sure everything is working. If you have any problems an applications expert at ISIS is available to help you troubleshoot your system. They can take you through the process step by step to make sure that you’ve got everything properly installed.
For instantaneous system monitoring,...
For instantaneous system monitoring, the ISIS inSIGHT diagnostic module is now standard with both the 2-Cell and 3-Cell starter kits. With it, you can ensure that your electrical system is functioning normally and that all electrical connections are intact. It comes already installed into the Mastercell input unit and you’ll instantly see the status of every power output connected to the system. This diagnostic tool displays information on a back-lit, high-intensity blue screen. The four-line, 16-character display is easy to read in all light conditions. It allows for simple and quick diagnostics and troubleshooting of the system installation. The instantaneous indications allow for quick testing of electrical functions for all inputs. Real-time monitoring of critical parameters for all cells in the system gives you continuous access to automobile electrical system status.
This photo shows the available...
This photo shows the available inLINK remote control option that’s available with the ISIS system. It’s similar to traditional key fobs in form but offers much more in the way of function. It allows you to control all of the electrical functions on your vehicle from a distance of up to 150 feet away. To use inLINK, simply press the button to send a message to the Mastercell input unit. Just as when a switch is flipped inside the car, the specified output is then turned on in the Powercell control unit. The fob has four pages of functions. Page one includes enable security, disable security, operate headlights, and operate parking lights. The security function doesn’t lock the doors. Rather, it disables the ignition and starter in the car via the Mastercell, thus protecting the vehicle from thieves. Any output can be tied to the security function, locking it out unless it’s unlocked via inLINK. When activated, the lights on the car will flash a short pattern.