Wire harness rebuild or replace

Fuelie74

Well-known member
Joined
May 7, 2008
Messages
770
Location
Monroe, WI
Wanting to address my wire harness issues in my 74 and am looking for opinions of if I should instill a painless harness or rebuild the one I have. It was butchered years ago when I bought it and my modifications haven't helped. The fuse block is broken and hangs loose and the car has many electrical gremlins. I currently have part of my dash out to put a heater core in and get the HVAC rebuilt and working correctly, so now would be a good time to fix this. I have a new painless harness that I bought at a swap meet several years ago plus a 73 and 76 parts car to donate their hardnesses.
 
Old g/f of mine had a '63 vert.....with a rusted out fuse block, and I have seen others including my '72 vert with same troubles....The fuses themselves tend to melt the solder between the element and the metal caps, due to the steel clips on the block/holder being corroded, and then they were never soldered to the copper bus plates, just crimped over, I have seen those crimps give up the ghost and start getting all burnt and dark looking, dropping voltage of course, and causing fuse failures as above....

the remedy seems apparent, clean and solder all connections including where the wires are fastened down...polish up the steel clips....

In all the cars I have had over the years, I have never bought a new harness for any of them finding plenty of length in the old wiring to cut/strip/tin the wire ends and solder down....course I don't mind rerouting at all either....like in my '72 here, only section of that firewall plug that is left is the front lighting, all the rest is disabled, and wires run up higher near the gas pedal cable, and making it easier to work with, no plug at all, I had one of them mess up BIG TIME decades ago, I pulled out clip leads and a jumper cable and drove the car home that way....never did act up again, nor could I find what failed but it was in that damn firewall plug somewhere....:crutches:
 
The interior firewall harness of my 70 had been buggered up by Bubba. The harness wires for the original radio and original speakers had all been clipped and modified. A custom radio, amplifier, speakers system had apparently been installed.....along with a custom burglar alarm system. All of this custom stuff had been removed before selling the car to me....so I had a lot of wire mysteries. I started out trying to work to save the original harness, but lacking factory original connectors was a daunting problem. I finally gave up fighting, and bought a new Lectric Limited repro interior harness for $512.
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By the Way. If you're working on building custom wire harnesses for you car, making harnesses that look professional is difficult. For my 68, I bought Packard Electric OEM connectors, etc, but I had to buy in volume so even though the individual connectors and parts were not that expensive, that I had to buy a lot of unneeded parts drove the price up.
 
I had thought about going that direction. The big thing stopping me is that my car has been modified. The addition of efi wouldn't effects the dash harness much but somewhere along the way all of the interlock stop was removed and that makes me think I will be doing a fair amount of rework to the new harness.

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Look into American Auto-wire in Bellmawr, NJ. You can get their stuff through Rock Auto and get an additional 5% off. It's tricky to find on the Rock Auto website, you may have to use the search feature. I have one of their engine harnesses on my 71 Skylark and it is spot on.
 
I ended up deciding to rebuild the harness out of my 73 parts car. Unpinned some wire out of my 74 and 76 parts car harnesses to make a good dash harness. Then I added the wirers to the harness for my 75 electric tach.

I also replaced several of the larger power feed wires. I bought packard 56 and 59 terminals so I could do it right. The main power feed from the battery to the left fender I upgraded to 8ga.

Anyone know what the black stuff is the factory used to seal the firewall connector?

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I ended up deciding to rebuild the harness out of my 73 parts car. Unpinned some wire out of my 74 and 76 parts car harnesses to make a good dash harness. Then I added the wirers to the harness for my 75 electric tach.

I also replaced several of the larger power feed wires. I bought packard 56 and 59 terminals so I could do it right. The main power feed from the battery to the left fender I upgraded to 8ga.

Anyone know what the black stuff is the factory used to seal the firewall connector?

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I have been using this wherever a flexible black seal is needed on the car. I have successfully fixed a loose back window on a '77 Vette and I also used it on my '71 Skylark to caulk the trunk seams. It looks factory when it's cured.
http://www.homedepot.com/p/Loctite-...e-Roof-and-Flashing-Sealant-1675273/203163733
 
Anyone know what the black stuff is the factory used to seal the firewall connector?

I'd assume it's 3M caulking...it's available in black and white. I don't have the part number handy right now. It's extensively used on the C3's and other cars. Underneath the stainless steel trim of the windshield, the body stainless steel trim to interface the T tops. At room temperature, it's maddening stuff to work with...it sticks to your fingers. Before using it, I put it in the deep freeze to make it stiff. It comes in corregated sheets of ribbons. You tear off sections to work with. When chilled, it's then workable. Seems like the number 777 comes to mind.
 
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