Burned wires, upgrading fuse box, need help...

[Raze]

I measured some of the wires in the harness and it looks like the majority are either 14 gauge or 10 gauge but I wanted to ask to be sure so I can go get all the correct sizes. I finally have all week to work on my spider, and the most pressing task is getting the electrical sorted out. I disassembled the dash, unhooked the gauge cluster wiring, and began working on disassembling the fuse box and upgrading to a modern blade style box. I did this because the main power fuse has partially melted into the fuse box housing. There are no less than 4 burned wires in the harness, one going to the ignition, one that runs to the ignition coil (under the hood all melted) and a couple others I haven't identified yet. The car runs and drives regardless but I don't feel safe using this car like this. Therefore I got a new fuse panel and printed out Artigue's wiring schematics. I plan on going through each circuit one at a time and testing everything and replacing or rerunning lines as needed (i'd like to run a whole new harness but I want to start getting things working first). Any help is appreciated!

[azruss]

First, you have my condolences. You may be too deep into it by this point, but first i would figure out what works and what doesnt. Next i would find the common element in the 4 burnt wires. Usually a ground short creates such nastyness. Next, take digital pics of everything as you go. Makes it much easier to go back and find mistakes. Brad's schematics are awesome and you will find the Fiat had no problem substituting different color wires on occasion.

[Raze]

yup, way ahead of you, that's basically what I'm up to, I got all exterior lights working (minus rear driver side side marker due to bad positive cable), I got the radiator fan working, no wipers, gauge lights working (no gauges working presently), starter, ignition system (car runs and drives as stated), no stereo.

I need to know what size wires the harness is comprised of, I bought 10, 12, 14, and have 16 and 18 gauge laying around. I just don't want to create problems repairing the burned up wires.

-Jeff

[mdrburchette]

10 to 14 seems to be what I've come across in the harnesses I've pulled from Fiats. Of course, replacing a wire with a larger gauge doesn't hurt a thing.

[Raze]

That's what I wanted to hear (I knew the part about going bigger, but I didn't want to go smaller on anything and just wanted to be sure)

[Raze]

So I learned more about the car today. I cut most of the electrical tape (38 year old) from the harness under the dash and began retracing all the lines to and from the fuse block along with removing the melted wiring. All of the melted wires, a black ground line, a white and light blue line, and a brown line had all been previously severed from whatever they connected to long ago (I haven't retraced all the lines yet but it appears one was the line to the brake indicator lamp (white/blue line) which was spliced back in via the other good one with a yellow wire that must have come from one of the missing gauges/interior lights (like I said I haven't gone through it all). The brown one was connected to another line running to the stereo which was wired in horribly and which I think was the original source of the melt down.

Additionally the rear parking lamps are not on when the lights are on but rather the rear turn signals are on, as are the front turn indicators instead of the front parking lamps. seems rather backwards but straight-forward to fix, just have to find where they buggered the connection, my guess for now is the aftermarket 3position toggle switch.

Relay time: I need help on how to test the brake switch, is there a procedure? Is there a flasher relay? If so what one is it? How do you test it?

I haven't removed the front deck lid which contains the wiper motor assembly but will as it doesn't seem to be working either.

One last question, I'm trying to upgrade my fuse box to something like: http://www.mirafiori.com/faq/content/fu ... eblock.htm but I'm noticing on the stock fuse block the upper connections look 'disconnected from one another, but the bottom seems connected between 3-4, 5-6, 7-8, and 9-10 with 1 and 2 on separate isolated circuits. If this is the case, and I'm running a new ATO style, do I need to mimic this (in order to place the max load possible across that circuit given all the different systems running on that circuit) or should I break them down and place each grouping on their own circuit with lower amp fuses?

Any more info I can get on the conversion process would be most helpful!

[spider2081]

Have you considered looking for a used wire harness?? I don't know what year your car is but someone here may may have a good used harness. I think this would save you a lot of time.
There are a few manufacturers of fuse blocks and Littelfuse makes at least one with relays on it. I had the part number for it but can't find it at the moment.
Last thought is you might get a fuse block assembly from a modern car at a junk yard that has enough fuses and relays to do what you are thinking of. Having the relays part of the assembly would be a time saver.

[Raze]

Have you considered looking for a used wire harness?? I don't know what year your car is but someone here may may have a good used harness. I think this would save you a lot of time.
There are a few manufacturers of fuse blocks and Littelfuse makes at least one with relays on it. I had the part number for it but can't find it at the moment.
Last thought is you might get a fuse block assembly from a modern car at a junk yard that has enough fuses and relays to do what you are thinking of. Having the relays part of the assembly would be a time saver.

not many 'good' used harnesses from an early model spider floating about, or one I would trust more than this one.

I'm not worried about combining relays with fuses, I just wanted more insight into how to properly test the relays, i.e. circuit paths since these older model ones don't necessarily show all the paths on them like many modern ones do.

I have a modern ATO style fuse block with enough fuses to replace the euro-style one, my question was regarding circuit paths on each fuse as it appears the bottom of the fuses are coupled after the #2 position fuse.

[Raze]

Nevermind about the brake light switch, hazard and turn signal relays, they're all working properly, still not sure about the fan switch but i'll sort that one out later.

I finally got all the lights working correctly and wired to factory setup, the PO had switched front turn signal and parking lamps, also changed rear turn signal lamps to running lights, brake lights didn't work (turned out to be a blown fuse) and the signals didn't work. I corrected all the miswired crap and now all my lights (sans backups are working). I even got all the side marker lamps running and fixed my low-beam/high-beam problem.

I'm down now to getting all the gauges working, radiator fan switch working, wipers working, and stereo and then I'll be able to rewire the fuse block.

Basically I want everything 'working' before I redo the block so it's easier to diagnose issues later on.

[Raze]

Got everything working except the stereo as it looks like the original culprit for the meltdown. I also did the brown wire fix and it seemed to speed up the turn signals and increase the headlight brightness. Wipers are slow as dogs but it's not the motor or electrical, the actual rods were rusted/seized. Took a bit of penetrating oil and time to work them loose and loosen them up but they're not as loose as I would expect them to be, but at least they move, I never plan on driving this thing in the rain since the top isn't water-tight.

I also had to patch the the driver's side drain dish as it had rusted through (1 spot of rust I've found so far). I did a quick patch with sealer then wire mesh backing and bondo for now. I got matching paint and hit it with a few coats then topped it off with clear coat. The whole tray area is now well sealed and in good shape. I just wanted to stop the rust for now, maybe someday I'll fix it correctly.

Tomorrow I was planning on finally redoing the fuse block to a new ATO style. Hopefully it'll go as well as all the rest of the fixes which have all gone fairly well after I removed all of the crappy old electrical tape holding together the harness bundle under the dash. I mean honestly that one step saves so much pain when troubleshooting your electrical it's comical.

[mdrburchette]

Keep up the good work, Raze. I'm following your progress and appreciate your posts.

[Raze]

well new years slowed progress. I isolated all sorts of problems due to the aftermarket stereo, looks like the power button is illuminated when plugged in, it's running power through the fuse block off of the line to the cigarette lighter with a separate 15A inline fuse, then it's running a separate power line from the ignition switch to a 4 prong plug which runs into the stereo. When I plug this in, lights stop working, and all sorts of 'fun' things happen. Looks like I'll be redoing the stereo from scratch, most likely ditching this all together. The new ATO style fuse block will have a separate line just for the stereo, I figure that's alot safer than how the PO put this together.

[Raze]

Figured I'd post some progress:

Started figuring out how Matt Webb did his wiring job into a new ATO style fuse block, what a PITA, I have to go get a bunch of larger spade connectors (covered kind as I hate the bare ones) and I'll do all the cross-wiring and plug it into the new fuse block:



Mine is the one in the background (12 position) but the circuit fuses aren't linked so I'll have to run connection wires between the lower half of the circuits (if you inspect your fuse box, the lower connectors cross between circuits). I finally figured out how Matt Webb did this by basically connecting the wires together and splitting them across the fuses with extension wires. When he says: "Also with the old block some of the spots are actually junction points for more than 1 wire. I just removed these points, soldered the wires together and soldered my extension pigtails to them. don't forget the heatshrink tubing."
(quoted from http://www.mirafiori.com/faq/content/fu ... eblock.htm) what he forgot to mention was that the junction points not only have more than one wire (usually more than one for the lettered side of the block) but that the lower connector to the barrel fuses actually connect, which is why in his pictures each points worth of wires when pigtailed (the larger gauge red wires and the black wires) runs to two separate fuses.

Also, ATO style fuses have 7.5A which on 16ga wire is the max you should safely run, while I'm not positive that there are 16ga (I measured mostly 10ga and 14ga wires) the fact that the original fuses are 8A and 16A leads me to believe I may try running 7.5A first and if they are insufficient or give me trouble I'll step up to 10A, likewise I'm going to start with 15A fuse for the 16A barrel fuse and work my way from there.

The nice thing about the fuse block I bought which cost $30 shipped to my door is is has it's own self contained plastic housing with bolt holes (the inner will bolt right in to the original hole, the other just needs a small extension on the outside but fits in the stock location. It also has covers built into it and is designed for marine applications so it's well built and rugged.

I've got to work on getting the suspension back on my track car this week so hopefully I'll get some time next week to work on the Fiat again. I still have to sort the charging light to the alternator (see if it still works), the temp switch to the rad fan (replace the fan since the blades are falling apart) and it's wired in to a switch on the dash, and get the gauge cluster lights/sensors all tested and working. Almost there!

[NGinuity]

All of the melted wires, a black ground line, a white and light blue line, and a brown line had all been previously severed from whatever they connected to long ago (I haven't retraced all the lines yet but it appears one was the line to the brake indicator lamp (white/blue line) which was spliced back in via the other good one with a yellow wire that must have come from one of the missing gauges/interior lights (like I said I haven't gone through it all). The brown one was connected to another line running to the stereo which was wired in horribly and which I think was the original source of the melt down.

Are you sure the black wire was a ground? Test it real quick with a multimeter and see if it beeps when you touch the metal bottom of the dash. If it doesn't, then it's likely one of the wires on the back of the ignition harness (the piece likely missing and taped around). When in "RUN", the black wire connects to the pink wire via the ignition switch to power fuse #1 and the ignition coil. That particular black wire should be connecting to the alternator via the fuse block #9 and #10 if you want to check.

The brown should be your constant hot coming in through the firewall, and the light blue feeds the headlight circuit. If you've got the time, this is the circuit you wanna put a relay around on the backside of the headlight switch. Your ignition switch, and headlight switch will run MUCH cooler.

Where'd ya buy that fuse block? I like it! I emailed Matt about his mod, but haven't heard back yet. I have a similar idea that uses panel mount ATO fuses that snap into the back eliminating the need to solder in the pigtails.

FWIW, I feel your pain. I'm in the middle of "fixing a fix" where the ignition harness caught on fire and burned up the wire going to the headlight switch and that blue/red wire that feeds the fuse block to the wiper circuit. The PO just jumped around it, unfused.

Upgrade to the bigger wire whenever possible. It's drastically undersized for what it does, especially the headlight and heater circuits.

[Raze]

Honestly I can't remember where that black wire went as it just terminated in the dash, and I don't have the stock dash, or all the items like a cigarette lighter, interior lights, and a few other things are missing, so there were spare wires used to splice around some of these burn-ups. The brown wire wasn't the larger gauge, it was a smaller brown wire, again, can't remember off the top of my head which circuit I figured out it went to. I ended up retracing every circuit by hand to ensure proper operation. I'm also missing the smog equipment so there are a few more extra lines. Also, the mechanical fuel pump was removed in favor of an electrical in-line pump which gets it's + off one of the ignition coil spades. I need to put an inertial switch or something to kill it in the event of an accident, right now it's on all the time when the coil is energized.

I did the brown wire mod as well to upgrade power to the ignition switch, everything is much more stable/brighter which is nice.

The fuse block is from Wirthco, but I got it through a parts vendor since they don't sell directly. I'm actually not planning on soldering my ends together, I'm going to use multi-stranded reducing butt-connectors for simplicity and easy of modification in the future.

I haven't had any time to work on it, but hopefully this weekend I'll get all the connectors I need and get back on it...