I will offer full disclosure here – the decision to finally implement the plan described in the previous post started out as a decision to remove the transmission and address its issues. My parents were leaving for a vacation while I opted to stay home and work, so I was hesitant to tackle a job like the transmission for fear of being overwhelmed or doing damage. Nevertheless, I thought I could do some prep work, such as removing the center console to access the shift lever and disconnect any plugs. As I dug into the car’s interior, something happened that I didn't imagine would: I became even more scared about the state of the car’s “functional” electrical system.
It had become apparent to me that my car should not be driven much longer without a complete overhaul of the electrical system. To give you some kind of an idea of what I discovered as I removed the existing harness, there was an AC power cord with both leads stripped and wrapped in electrical tape on one end, and on the other attached to a small transformer, which had no other outputs of its own. Perhaps it was this same electrician that completed a circuit by splicing a black 14 AWG wire into two 16 AWG wire, back into a black 16 AWG wire, and finally into two 16 AWG wires which split into their own separate circuits, one of which had an inline fuse in addition to the one in the original fuse box. Beyond this were the burned connectors (like the one responsible for the no-starter problem that I faced when I first purchased the car), a melted wire from an electrical fire, a rat’s nest of wires left in the engine bay after I had removed the emissions equipment from the car, and a half-baked solution to the lack of turn signals. Among the components that didn't work before beginning this project were hazards, reverse lights, courtesy lights, engine bay lights, the trunk light, the handbrake on/low brake fluid warning light, the seat belt warning light, and at times even the turn signals. Needless to say, proper repairs were required. Before long, the car had begun to look like a jungle of very colorful spaghetti.
This is what happens when automotive electricians have too much pasta in their diet.
Before completely removing any wire from the car, I used a label maker I had purchased for this job to label as many of the original wires as I could. My hope is that this will make the harness more useful to someone else who might need it, since a good portion could be salvaged. Once that tedious task was completed, I went about disconnecting everything and, before too long, I had the harness in my hands!
Although it took some time, having the original harness labelled could prove to be convenient if it ever needs to be reused, and it served as a good reference when building the new one.
At this point, I had already purchased many of the materials I would be using. I was attempting to do the best job I could with relatively inexpensive materials, so the wire I used was PVC coated from EBay and not GXL wire like I would have preferred, given enough money to spend on the job. Also from EBay, I had purchased LED replacement bulbs for all of the lights; a roll of flexible LED strip to use as courtesy lights; Bosch-style relays, including two electronic flasher relays for the turn signals and hazards; expandable, braided wire loom; a 4 gauge wire for bringing power to the fuse box; a high-current, solenoid-style relay (typically used as a starter solenoid for lawn tractors) to activate the “switched” section of the fuse box; plenty of heat shrink tubing and a heat gun to apply it. During the project, I also purchased dielectric grease, crimp-style spade terminals, and a set of automotive-style multi-pin connectors. These pin-and-socket style connectors allowed me to create up to 15-wire connections from the harness to the vehicles components so that one could be removed without the other, similar to the way the original harness is. The total cost of the project was less than $200, including the $50 fuse box from blue seas.
At this point, the car was free of 95% of all wires, and it was time to begin the construction process. Before that could happen, however, I needed to determine where the fuse and relay box would be located, and that meant designing it to know that it would fit. I fired up SolidWorks on my school laptop and began working with the sheet metal tool to sketch up some basic designs. The goal here was to shape something that all the electrical components would fit into comfortably and that would fit into the car comfortably, in addition to being simple and easy to manufacture quickly, since I would be asking the engineering model shop at my father’s workplace (and my previous summer employer) to help me build it out of stainless steel. The design I chose was based on locating the box on the left side of the engine bay. This kept it relatively close to many of the high-power electrical components, such as the engine fan, headlights, radio, and horn.
This is a solid model that I created in designing the fuse box and relay containment box.
Building the wiring harness was relatively simple, now that all the planning had been done and I had a clear idea of what I was doing, but it certainly took a long time. Using one of my spreadsheets, I was able to sort the list of components to show all of the wires that departed from a certain location (the steering column, for example) or those that arrived at a certain location. Using these lists, I would run a wire from one its origin to its destination, leave some excess length to ensure that there would be enough, cut it from the spool, label the wire, and add the wire color to the spreadsheet. By doing the job this way, I was always aware of which wires had not been added to the system, and it was easy to determine where I needed to work next. Slowly, but surely, I created my own forest of spaghetti, and soon took to bundling it with cable-ties.
A bundle of newly run wires can be seen exiting the firewall and running down the driver's side of the engine bay to the location of the new fuse/relay box.
When the wires were cut and bundled, I pulled the beginnings of my harness out of the car to begin attaching the multi-pin connectors. All connections on the harness remained female, just as in the original, so the task was methodical and tedious, more than it was challenging. The end of each wire was stripped, crimped into the pin (I had only a needle-nose pliers to crimp this style of pin), soldered for safe measure, and protected with heat shrink tubing. By the time I had finished more than 120 connections on the harness alone, I was quite proficient at this process.
Some completed female pins: crimped, soldered, and heat shrink-wrapped.
Before the pins could be inserted into their connectors, I wrapped the harness in the expandable wire loom that I had purchased, using electrical tape to prevent fraying at any junctions or ends were the loom had been severed. Once the loom was on, I began inserting the pins into their respective connectors. Determining which wires belonged to which connectors was done carefully, as there is a limit to how much current can be run through each size connector. I kept track of which wires were in which position in yet another spreadsheet that I put together. Before I knew it, the wiring harness had been completed! The next challenge was to wire everything that would connect to it.
I decided to make some changes to the switch layout by removing the existing panel in the center of the car’s dashboard and replacing it with a panel that contained switches and indicators which were more useful to me. Five switches were used for lighting (night, parking, and off), courtesy lights, hazards, wiper motor speed, and engine bay lights, while four LED lights indicated turn signals/hazards, and handbrake on/low brake fluid level. While I had to wait some time for the panel itself to be fabricated, I was able to wire all of the toggle switches (toggle switches aren’t legal in production cars anymore, but it is such a classic look that I couldn’t resist!). One-by-one I crimped terminals and ran wires, putting pins on each and plugging them into their connectors. The gauge panel, the control panel, the headlights, the wiper motor; I whittled the list away until I faced the fuse box.
In this photo, two 4-wire connectors can be seen, which allow a secure and protected connection within the circuit; above them, one of the LED strips used to illuminate the engine bay can be seen.
I had to open the fuse box up and literally sever the bus bar that connected the input terminal post to each of the fuse positions. I drilled a hole and inserted a new post, then connected that post to the disconnected section of bus bar. After this came the challenge of putting wires on all of the correct terminals – a task that was, once again, aided by my spreadsheets.
The bus bar inside the fuse box was separated, and this section was connected to a separate terminal post which I installed into the fuse block.
The separated bus bar is shown re-installed in the fuse box. The machine screw acts as a secondary terminal post for the "switched" power input.
The finished product can be seen with two power inputs: the right input is always live, while the left is energized by the ignition switch.
At this point, I had completed wiring the electrical system. I have spared you some of the monotony, describing the construction in mere paragraphs, but in my mind this seems more an epoch than a journal entry. Nevertheless, the most rewarding part is to come, for we have reached the part of the story I have been so anxious to share with all of you – the results. After everything was properly installed and the car’s interior was reassembled, I gathered some pictures to share with everyone.
This is the completed fuse/relay box, in its final resting place.
With the fuse and relay box opened up, fuses are easily accessible, and the relays that lie below are identified using the labels on the box walls.
This is one example of the braided wire loom where the harness branches off in two directions. The loom is secured using electrical tape and reduces clutter, while still allowing airflow to the wires (increasing current carrying capacity slightly). The speaker wire and ground wire have since been secured behind the dash, but this photo was taken before that was done.
My goal was to have the car completed in time for my aunt’s 60th birthday celebration, since my family would be coming from around the country to visit us in Door County. I wanted to show off my baby, and not have her in a tangle of wires in the garage! Mission accomplished. Frankly, I was surprised at how well everything turned out. Admittedly, I ran into a few issues in the first attempt to energize the system. Several fuses blew, indicating that I had shorted out the internals of my fuse box during modifications, but I was able to remove it, open it up, and make adjustments in a matter of a couple hours. I found that I had accidentally mis-matched the high-beam and low-beam leads for the right headlight, which led to some entertaining confusion prior to their being switched appropriately. I have put at least 150 miles on the car since the rebuild and everything is working just as I intended it, which makes me extremely pleased!
Two more sheet metal parts that I had assistance fabricating were the switch panel and the panels for my new speakers. I am not entirely sure if the speakers in the car were installed by FIAT or by a previous owner, but I can only assume the latter. The speaker faces were 6" x 6" squares, protruding from the inner door panel. As a result of this, the window crank would hit the speaker, damaging both components. This seemed like an excellent opportunity to upgrade my audio system! I purchased 3.5" round speakers made by Polk, then designed adapting plates that would cover the original speaker holes and use the same mounting points. Once they were made, I took a wire brush to them to get a nice brushed surface finish.
The speaker panel uses the same mounting holes as the old speakers and covers the old hole, while allowing the window crank to clear. I used a wire brush to give the stainless panels a softer look.
The switch panel is a custom design and actually incorporates the golden ratio several times, for those of you who are aesthetically inclined! The challenge with the panel was fastening it to the dashboard. I had to cut out the metal backing plate that held the original center dash in place so that the switches would fit. I eventually decided that magnetically fastening the panel to the dash would make modification easy and avoid fasteners ruining the look of the dash that I had intended. I bolted four rare-earth magnets in the corners of the mounting location with spacers to offset the panel somewhat (for switch clearance). The panel itself was austenitic stainless, so it was not magnetic. To create a magnetic surface for the magnets to stick to, I grabbed some 1" wide strips of ferritic stainless steel and bonded them using 3M VHB mounting tape (awesome stuff). The panel snaps right into place (the exact position is adjustable) and doesn't move at all during driving or when using the switches.
Four rare-earth magnets hold the switch panel in place. The offset allows the switches and wires to clear the upper heating duct.
This switch panel was laser cut from engine turned stainless steel. The five switches, from left to right, select wiper motor speed (high/low), courtesy lights (on/automatic with open doors), exterior/dash lighting (off/park (dusk)/night (on)), trunk lights (on/off), and hazards (on/off). Below them, the outermost red LEDs blink with the right or left turn signals, respectively, or the hazards, while the inner two indicate low brake fluid or an active handbrake.
There were a couple of things that I did not get a chance to wrap up before leaving for school, but it is something I look forward to finishing in the future. My wiper motor controller was malfunctioning in some situations (likely due to a subtle error I made in my coding that I was not aware of), so I temporarily programmed the Arduino controller to turn the wipers on or off, rather than accommodate the delay function that I had hoped to include. The existing switch on the clutch pedal is a normally open switch used for the emissions system, but I hope to replace it with a normally closed switch so that I can use it as a “safety switch” that prevents the car from being started without the clutch pedal depressed.
This circuit switches the relay in the fuse box that brings power to the wiper motor. The black microchip is a programmable micro controller designed to operate using open-source Arduino software.
Other than that, I simply have to wire and mount a snap-action switch that activates the trunk light as the trunk-lid is opened. I look forward to completing this, after seeing the results of my other courtesy lighting. I have three courtesy lights in the cabin which can be turned on manually or are activated when either door is opened. One light is in each foot well, while the third hides behind the mesh panel below the stereo and is completely invisible until it is turned on! The engine bay lights have already come in handy for a fuse change that I had to do at night during the first headlight testing. They illuminate all of the areas of the engine bay that might need attention: carburetor, dipstick, fuse box, etc. Very handy!
Three LED strips illuminate the foot wells and the center console (where keys might be sitting in the dark). *I apologize that there isn't a better photo, perhaps in the future I will change that!
A teaser shot of how well the engine bay lights illuminate the under-hood area.