Chassis Construction
Electrical System

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We've elected to fabricate and install the electrical system ourselves for a number of reasons including cost, time and the ability to create exactly what we want.  We have some experience in the subject and don't believe that we'll regret this choice later...

We'll be using high quality components and wire throughout and will endeavor to complete the job to a high standard of durability, reliability and function.  Some of the work is already done for us; the engine came with a "Sakata" harness tailored for it and a MoTec ECU.  We'll only need to plug all the connectors into the correct sensors and supply power, ground and an ignition switch input.  We chose to purchase a "Switch Pros" 9100 - an eight circuit electronic switch/relay/circuit breaker unit that eliminates the need for us to create all those systems...  We'll still be responsible for all the basic things; radio, GPS, intercom, lights, starter, etc..


"Reverse" micro switch
We mounted this micro switch to sense when the transaxle is in reverse.  Our rear tail light unit has white "back up" lights that we want to use and the transaxle gear position indicator can also display "R" when triggered to do so.  This micro switch will control a relay for the actual load switching; it's own contacts aren't rated for the required amperage but can easily control a relay for working loads.


Ignition switch wired
This photo is of the early stages of wiring the dash - we still need to wire the instruments and "idiot lights".  The challenge is keeping it neat, orderly and secure while ensuring that everything works as expected.  The multi-conductor wire visible is for the gear position display - we'll be installing a 6-pin connector on it to mate to the cable that comes from the "sender" mounted to the transaxle.


Center Console "Back" Panel
This panel closes out the center console on the "back side" (towards the front of the car).  We've chosen to mount all the terminal strips, relays and circuit breakers (aside from what's contained within the "Switch Pros" unit) here for easy access and neatness.  None of the wire, relays or terminal strips will be visible once the center tunnel and console are final installed; it'll still be easily serviceable when necessary.  We'll have a terminal strip for the ignition "RUN" items, one for the ignition "ACC" items, a "LIGHTS" bus and a "GROUND" bus.  The circuit breakers protect the powered buses and the relays are for the horns, reverse (back up) light and manual control of the radiator fans.  The Switch Pros unit handles all the other switch, relay and circuit protection requirements.


Center console back panel installed
With the back panel installed, all the bus bars, relays and wires are contained inside the center console.  This makes for a tidy installation that's easily serviceable when necessary.  Visible are the three circuit breakers that protect the "Run", "Acc" and "Starter" buses.  All the other circuits are protected by the "Switch-Pros SP9100" unit.  It takes the place of conventional switches, relays and circuit breakers for up to eight individual circuits.  We're using only five of the eight circuits for now but plan to expand in the future (fresh air pumpers, rock lights, etc.).


Oil Temperature Sender
All of the engine information "senders" are "one wire" senders.  Each sender has a single wire going to the respective gage which also has power and ground connections installed.  The gear position indication system has a few more wires to indicate reverse and for dimming the display when the headlights are on.


Protective sheathing on wire bundles
We did our best to protect and secure the wire bundles for reliability and long life.


It's "Alive"!
Everything works as expected; all the lights, fans, pumps, radios, instruments, etc..  We have only the horn buttons remaining to be connected; we want to be able to remove the steering wheel so we'll need to be able to disconnect the horn button wires when we do so.  We'll also need to provide for the rotation of the steering wheel; we'll be using a coiled cable to allow some "stretch".  The coiled cable will be fitted with a quick disconnect to allow for removal of the steering wheel.  


Removable steering wheel cable
We want the steering wheel to be removable from the car for security reasons - that means that we need to be able to disconnect the horn button wiring.  We used a coiled, multi-conductor cable to permit free movement of the steering wheel while in use and installed a male helicopter headset plug on the free end.  The steering wheel has two buttons, wired together in parallel for the horns.   Our original plan was to separate them to use one for the horns and the other for a radio transmit button.  We later chose to leave them configured for horns only and mounted a dedicated radio transmit button for the driver on the dash.  We expect that the co-driver will do most of the radio communications anyway.


Helicopter headset plug
The helicopter headset connector allows four different wire connections to be made - we chose these because our original plan was for the cable to carry both horn and radio switch signals.  Having decided to use the steering wheel buttons for horns only, we'll now use only two of the four contacts.


Horn cable installed and functional


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