Advice/tricks for re-wiring 850 coupe

Discussion in 'Rear-Engine Fiats' started by dnudelman, Nov 14, 2019.

  1. dnudelman

    dnudelman Daily Driver

    Location:
    Glendale AZ
    Hello folks,
    My 850 coupe has the wiring harness cut and removed on the drivers side from the seat forward. The switches, gauges, fuse box are still in place but loose and cut wires dangling.

    I have a spider wiring harness that I can scavenge from. I have a 2nd coupe that I can use as a guide. I have wiring schematics for both 850 coupe and 850 spider.

    Any tricks I should know about from those how have done it before?

    Thanks,
    David
     
    Frank L. Di Gioia likes this.
  2. Frank L. Di Gioia

    Frank L. Di Gioia True Classic

    Location:
    las vegas, nevada
    Consider dipping all the plug-in connections in a mild acid solution to insure "fresh" copper contact areas. I can't remember but I think I used a diluted pool acid. Experiment on some throw away plugs first. If splicing wires solder connectors after crimping and apply heat shrink tubing. Match colors or three years from now you won't remember that the red wire was green when it arrived at it's destination..... Use a good quality electrical tape to wrap the finished bundles. Clamp in a padded vise and stretch the bundle as you spiral wrap it for a good looking finished product. When wrapping overlap by 50%, meaning you can see the last leading edge line up with the trailing edge . Hard to visualize but end result is a 1" wide tape will have a 1/2" spiral seam, make sense? Small black plastic ties at the ends keep the tape from unraveling. Ask yourself why you devote so much time to a car you alternately love and hate..... Hope this saves you some time down the line.
     
    khnitz likes this.
  3. dnudelman

    dnudelman Daily Driver

    Location:
    Glendale AZ
    Thanks Frank. So you are suggesting for splicing using non-insulated butt crimp connectors, solder after crimping and insulate with heat shrink tubing?
     
    Frank L. Di Gioia likes this.
  4. myredracer

    myredracer True Classic

    I'm with the dipping the stripped ends in acid method. I use muriatic acid only because I have a bottle of it on hand. You have to be very careful so no drops land on your car or anything else and must rinse in water right away. Wire ends up looking like new. There are other acids and chemicals but not sure what works well or best. A lot more work, but I would consider redoing all crimp connections if you want a first class job. The copper on old wiring can be tarnished and possibly not make a good enough connection because moisture can eventually migrate between the outer insulation jacket and the wire quite a distance. Sometimes you can strip the insulation off a long length of wire and find the whole thing is tarnished. If you happened to have a wiring harness out and on the floor or a bench, it makes using acid much easier.

    Ordinary crimp connectors from an auto parts store are good. You could even use the plug-in style butt connectors. Fiat 600s had them under the dash. I see no need to solder connections and use heat shrink tubing but that is an option and will make a permanent long lasting connection. The wire has to be super-clean for the solder to flow well onto it.

    Crimp connectors with a heat-shrink jacket are available but a car isn't exactly in a damp/wet environment. Can't hurt tho. There's also a heat shrink connector pre-filled with solder that melts at a low temp. like here: http://www.quickcable.com/products.php?pageId=1033 Have never used them and don't know how well they work.

    Check all ground connections too as they can often cause problems when everything else is fine.

    If you have a wiring diagram that corresponds 100% to what is in your 850, consider yourself lucky. I just re-installed my 600 wiring harness and I couldn't find a diagram that had all the same colors plus a few connections/routing were different. Took many hours to sort it out... :(
     
    Last edited: Nov 15, 2019
    Frank L. Di Gioia and khnitz like this.
  5. khnitz

    khnitz Daily Driver

    3M Super 33+ is a great electrical tape that stays pliable in cold weather and keeps adhesion well.
     
  6. dnudelman

    dnudelman Daily Driver

    Location:
    Glendale AZ
    just bought a roll of 3m super 33, thanks. however cold weather not really a problem. High of 82 today ;)
     
    Last edited: Nov 15, 2019
    khnitz likes this.
  7. Frank L. Di Gioia

    Frank L. Di Gioia True Classic

    Location:
    las vegas, nevada
    The only ones I actually have are the plastic crimp connectors. After crimping I razor cut the plastic off and then solder/shrink seal it. Then I clean up the blood from the razor cuts..... A wire wheel will remove the plastic if you have it all out of the car without the blood and scars.
     
    khnitz and dnudelman like this.

Share This Page

  1. This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
    By continuing to use this site, you are consenting to our use of cookies.
    Dismiss Notice