The Restoration of a Vintage Fiat 124 Spider Wiring Harness

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Here we are at the final stages of actually getting our hands dirty and most importantly the dirt, rust and corrosion off your delicate wiring harness and its connection blocks on the 124 Fiat Spider. I have already provided you with a heads-up in previous articles how to better prepare yourself for the challenge both mentally, physically and how-to get armed with the proper tools, products and knowledge.

Now before you go ripping off that dash and pulling the bowels if you will out of the dash cage lets take a deep breath and relax. Three key items of the utmost importance to take into strong consideration in this work of cleaning and repairing the wiring harness or anything else concerning a – vintage automobile – restoration project for that matter is: 1) The vehicles age. My 124 Fiat Spider is 34 years old which leads me to: 2) Due to the vehicles age it may have had more than one owner. Which now brings me to: 3) Is that when taken into account the age of the vehicle, along with the possibility of the car having more than one owner and the fact that what one owner considers a repair job well done is another owners headache(s) later.

Trust me on this one, my Fiat was a diamond in the rough, it looked pretty good; I know I got allot of long-looks and questions from man, woman and child. It ran very well albeit the transmission lacked first gear due to a bent shifting fork. However on my first examination via on my back looking up from underneath the dash and what I saw on the steering column was quite a sight to say the least. Everything worked, it just was not done correctly because someone had made modifications and add-on’s, do’s and re-do’s. A fire waiting to happen and they can and will if your wiring has been improperly modified and or in disrepair.

My Fiat had an improvised ignition from some ancient Ford truck and several kill switches added on as to confuse a would be car thief. I do not know who I felt more sorry for the guy who was trying to retain his property with this make-shift theft deterrent “device” or a would be, very confused car thief.

Are you ready now? Alright then, lets go, — oh yeah — did you bring your digital camera? Digital camera you ask? For what? So you can capture those moments and prove to your wife or girlfriend that you still have the prowess and skills of an acrobat and that you still have it in you when your all twisted up in weird positions on the front seat of your Fiat.

There will be no soft-core photo shoots of you so they can grace the pages of Playgirl. No, this is a critical tool in this work of wiring harness cleaning and repair. If you do not have a digital camera, beg, barter, borrow or buy one. It is not absolutely needed and you can prevail without one but a digital camera is very helpful in the documentation of where everything was and where it will go back to.

Typically the dash can be extracted by removing four bolts just under the bottom lip of the dash board; one at each end and two near the middle off-set from each other. After the bolts are removed you should now try to get a feel for the dash; feel for its flex and for what range of movement it offers from that point. Your dash has seen allot of sun through the windshield not to mention that it’s a drop-top and it’s seen even more sunshine than your average car, vintage or not. They can be brittle and dry rotted and if the dash facade is in descent shape and can be simply cleaned and or a coat of spray paint especially made for plastic and vinyl you should handle with care. A new dash is several hundred dollars to replace and even a glue-on dash cover costs around $100.

To make things even easier you may consider removing the steering wheel via four bolts on the under-side plate connected to the steering column and one bolt from the steering column rod linkage. Wiggle the dash slightly to get a feel for it. Lift upwards until you hear and feel the seal break free from just under the windscreen and then pull it out towards you. I went all out and removed the seats as well and the thought to some of not having a seat to work from is disparaging but you will thank yourself later for the room you afforded yourself. A milk crate works well and goes in and out of the cock-pit with ease. You will on many occasions be a contortionist.

Now that the dash has been removed you will be in awe of all the wires exposed with all the their pretty colors. That or you will shudder in fear, begin to sweat and put the dash right back on. Armed with or without the camera sit there and just stare at it and take it all in and for a long time. I am serious about this, do not touch anything and just eye-ball it. If you have a camera start shooting. Start with just one section, seek out its origin and trail it to where it goes; doing this with your eye’s! Are you still taking pictures. Open your Haynes Manual, turn to the US version of the wiring diagram and confirm your recent tracking with the diagram on the page. The wiring diagram in the Haynes Manual is fine print and for some they may have trouble following the diagram, so if that is your case get something to magnify it and or scan a copy and enlarge it. Trace and follow each section and sub-assembly section and concur route with the manuals diagram.

Is it all dirty in there? I bet it is! Mine was very dirty and that is to be expected due to it being vintage and the fact it was an open air automobile. The smallest dust particulate over time accumulates and turns to dirt and grime with the culminating of moisture introduced into the scene. Get a portable shop-vac and carefully suck everything and anything out of there along the lines of dust and dirt. You may find this fiber insulation with a black sticky side to it that may be falling apart or sagging. Mine was both and removed and replaced with my own creation that I will be discuss in another article.

Okay now were going to get our hands in the belly of this beast and get started. As I mentioned above you should have long by now have studied the diagram and took a few photos of the over-all scene. Fill-In flash is strongly suggested as to give depth of lighting within the chasm of the dash cage. The Fiat 124 Spider has about 2-3 sub-assemblies depending on make and year that is attached to the main part of the wiring harness.

Using the instrument cluster sub-assembly (as photographed) of the wiring harness as a small example and great practice point of this tedious process you will find nine connection blocks two of which that connect to the main part of the wiring harness, typically white or red and sometimes both of the same color. If you do not have a camera mark each connection block and its mate with a symbol of your design so you know where it goes back to. After removing the seven remaining connection blocks that lead to the instrument gage’s put the gage’s aside for inspection and cleaning later; you will have plenty to do right now.

Take your bottle of Simple Green All-Purpose Cleaner; they say its concentrate and I tend to agree for I took mine and poured a portion into a small bucket of warm water and used a wipe, rinse, repeat process on the wiring harness with a rag. Spraying this into or directly onto any portion of the wiring harness that cannot be removed from the dash cage or near the firewall is not recommended.

You will want to proceed with caution now for as I mentioned before that the vehicle is old and you may encounter very dry and brittle wires and may be an indication as to stop and reconsider this project if it heeds and dictates to that of the age factor. Each vehicle has seen a wide range of elements and care, or the lack there of. Most are still pliable. A little tip and trick you may want to implement is to try leaving any natural bends on any portion of the wiring harness for it will serve you later when you replace it by memory and will be almost like fitting a puzzle piece back where it goes. Another rationale for this practice is again due to its age. Even if it is pliable take great care your hands may be the only ones to have touched this wiring harness since its assembly at the plant in Italy.

Carefully remove all electrical tape that is placed along the run of the wiring harness that keeps it into one collective bunch. Using your solution of Simple Green All-Purpose Cleaner and rag wipe down each of the many wires within the wiring harness, separating each wire if applicable as to get in among them.

Now that you have wiped down the instrument sub-assembly of the wiring harness were using for example and inspect it — thoroughly — for cracked wires or where shorts may have occurred. Replace any offending connection or fray with a 3M product and re-tape where it was removed from based on memory and or photographs.

Now check to see if the connection blocks are brittle and replace where needed. I suggest using 3M products for anything you encounter for electrical replacement parts. They have served me well and provide tight connections. Using a small wire brush try to work the bristles into the male end of each connection block that contains up to 6-7 individual flat prong connections and rid them of any corrosion that may be found. Now take your can of CRC Connection Cleaner as I made mention in “The Restoration of a Vintage Fiat 124 Spider Part III” which was about the useful products that may be used in this project and spray into the connection block. A little goes a long away, however if you get carried away do not despair for this product dissipates quickly due to the nature of the product made exclusively for electrical components. You will do the same for the female end but due to the many small holes you may want to shake out the female end to rid it of any excess product that may be trapped there within it.

After you have cleaned each of the nine connection blocks get your CRC Brand Di-Electric Grease Compound and fill each male connection block half-way to the top and wipe off the excess. This product prevents future dust, dirt and moisture from infiltrating into the connection block and will serve as an anti-corrosive measure for the future of you’re wiring harness.

When not dealing with easily removable sub-assemblies of the wiring harnesses get back to your memorization skills or your photos and study some more. There are portions that recess way back near the firewall that are not practical to remove unless conducting a full-body restoration. You will find for example near the front of the dash cage a steel beam that served as your anchor point for the dashboard removal/re-installation where a good portion of the wiring harness is attached to by bendable steel crimps that will allow you to leave the wiring harness virtually in place however a range of movement is allowed when the crimps are bent up and away as to clean, inspect and repair the wiring harness. There are many of these crimp tabs that secure the wiring harness in place that is routed thought and under the dash, they serve as road markers if you will for re-installation.

Study you’re wiring diagram, examine everything thoroughly before removal and if possible take as many photographs as possible. This practice worked extremely well for me and I have not yet had a problem with any wiring since. I discovered over a dozen infractions that could have cost me allot of time and money later down the road and on the mention of the road could have robbed me of many miles of driving time and enjoyment. I would in fact wager that the wiring harness is good to go for another 30 years plus. Good luck and God Speed…


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