How to approach wiring

[fiasco]

Going under the dash tomorrow to try to figure out what's up on the electrical end of things. Here's my starting point.

I have no existing controls beyond the headlight switch, and the switches on the column (wipers, high-beams and turn signals). I have no fan or heater controls of any kind (actually, there is no blower under the dash, so fan controls are a bit of a moot point).

Wipers do not work. The linkage moves freely and the motor's functionality is unknown.

Horn, headlights, parking lights and instrument lights all work. Turn signals act like I have one or more bad bulbs.

I have lots of loose wires under the dash - most are black and look like they were added by one or more POs.

What I want to do is wire up a number of accessories: courtesy light, one or more power outlets, car stereo, so I need to figure out where my live wires are and where my grounds are and I need to connect wires to accessories without accidentally wiring them into existing functions (like indicator lights or controls that would previously have been on the dash).

I know someone is going to want to tell me to go look at Brad Artigue's wiring diagrams, so I'll save you that trouble. The problem is that most of the wires I'm finding are black, and appear to have been added post-production. On top of that, I'm red/green colorblind, so any faded red, green, brown or gray wire (or stripe) looks the same to me. I also can't tell the difference between blue and purple most of the time. So a color wiring diagram really doesn't do me much good.

Is there a recommended approach to testing wiring for usefulness? Would I be better off installing new wires where I need them, and if so, what source of power should I come off of? If I add wires, what gauge should I use, and how should I deal with fuses (I do have an extra fuse box).

I have a test light, a volt meter, lots of motivation (though unfortunately not much patience) and a day off from work. Any and all insights, suggestions and humorous comments are welcome.

Thanks,
-- se

[jimincalif]

Be sure to pick up a jar of replacement smoke before you start, so you can replace any you accidentally let escape.




You asked for humorous comments, right?

Seriously though, from the sounds of it there is lots of unaccounted for wiring in there. Given that, my first inclination would be to spend some time trying to identify the factory wiring from the PO "improvements", and then remove as many of those non-functioning improvements as possible.

Wire size is based on the current of the device and the distance of the run in a DC circuit (both ways) to have something like a 3% voltage drop. You can find charts online that give you the wire size needed for a 12v circuit based on the amperage of the device and the distance. Fuses are sized by the load the wire can carry.

[fiasco]

I'll need a jar of that and a can or two of installation fluid before the day is out. I almost regret that I don't drink anything more lubricating than diet coke.

-- se

[halg]

Steve:
It didn't work for me to try and fix PO bad wiring while it was in the car. I removed the whole harness and layed it out on a 4x4 sheet of plywood, then you can see what is going on. After I replaced all the female connector pins everything has worked the first time. I don't know what your completion schedule is, but I would be willing to do the same for you. I am close (Pasadena) at least I could come look.
Hal

[fiasco]

Hal,

That's a very generous offer. This is my daily driver, and I really need to have it put back together by the end of the day, so I'm gonna be focused on doing what I can do vs. what I ought to do. However, I do expect that I will do the whole "pull it all" strategy at some point, and I will definitely hit you up for help.

BTW, I found my old heater blower in a box in the garage tonight (yea!) so that's another thing I'll be trying to get hooked up.

-- se

[halg]

When is your day off? PM me your address.
Hal

[fiasco]

PM sent.

[wikkid]

You may really need a helper, even a 4-year old one, to tell you the color of some of the wires.

[baltobernie]

... my first inclination would be to spend some time trying to identify the factory wiring from the PO "improvements", and then remove as many of those non-functioning improvements as possible.

My recommendation also. I'd suggest prioritizing electrical functions in a list. First would be stop lamps, IMO. Go down from there. You'll be getting rain in SoCal pretty soon, eh? I'll PM you a workaround for the wipers that bypasses the delay circuit.



If the harness is that chopped up, your inclination to replace the whole thing has merit. It took me about 50 hours to do mine (carb; not FI). I wrote an article on the subject that you're welcome to. Rewiring is not for the faint of heart, as there is no turning back; that's going to make such a job impossible on a daily driver. But the results are wonderful.

[fiasco]

I'll PM you a workaround for the wipers that bypasses the delay circuit.

I'd love to have that, thanks.

If the harness is that chopped up, your inclination to replace the whole thing has merit. It took me about 50 hours to do mine (carb; not FI). I wrote an article on the subject that you're welcome to. Rewiring is not for the faint of heart, as there is no turning back; that's going to make such a job impossible on a daily driver. But the results are wonderful.

Not sure I'm up for all that at this point (though I wouldn't mind seeing the article). Most of the important things already work (lights and such), but I do want to clean up all the bird's nests under the dash, and get a couple more conveniences wired up.

Thanks!
-- se

[mdrburchette]

Steve, it's not that hard to figure out the wiring harness on your early model Fiat if you have a factory diagram, but it will take time. Choose a circuit you want to work on, find wires in the vicinity of the component and start tracing them according to the diagram. Bundles of wires coincide with how the diagram is layed out. Good luck! Been there, done that.