How to replace a wiring harness
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Registered User
Joined: May 2009
Posts: 2,179
From: Northern California
How to replace a wiring harness
Just did this for perhaps the 3rd time in 35 years of owning a 66 98 convertible.
If you want to, have a solid weekend available for installation & in-car connector termination after a week or 2 of evenings prepping, cleaning & terminating a replacement harness on the bench.
I went fully formal with all GM/Packard 56 connectors and explicitly avoiding the junky crimp-n-go stuff. The big win for me was learning that you can get factory connector innards from lots of sources. Look for GM or Packard 56 connectors from 10 gauge to 18 gauge, both male & female for the connectors, plus the plastic insulator shells. But if you have a spare factory harness around, exhaust that first for originality.
I went from the extreme front of the headlights back to the fuse block, the removed as many connectors a possible from the dash. Then I pulled the dash...
I used a tiny german made flat blade to release the crimp connectors from their shells. This was invaluable on both male and female sides.
My process was clean all wires with lacquer thinner, just to get the cr*p off. Then use electrical termination cleaner on each brass terminal. I cleaned up a bunch of them with a dremel grinder, just enough to get the junk off. Or I reterminated and soldered as the factory had done (esp. the heavy gauge wires...)
If the old harness showed me the length, I terminated new connectors there, if not, I left it a bit long to allow for in-car clean up.
If you want to, have a solid weekend available for installation & in-car connector termination after a week or 2 of evenings prepping, cleaning & terminating a replacement harness on the bench.
I went fully formal with all GM/Packard 56 connectors and explicitly avoiding the junky crimp-n-go stuff. The big win for me was learning that you can get factory connector innards from lots of sources. Look for GM or Packard 56 connectors from 10 gauge to 18 gauge, both male & female for the connectors, plus the plastic insulator shells. But if you have a spare factory harness around, exhaust that first for originality.
I went from the extreme front of the headlights back to the fuse block, the removed as many connectors a possible from the dash. Then I pulled the dash...
I used a tiny german made flat blade to release the crimp connectors from their shells. This was invaluable on both male and female sides.
My process was clean all wires with lacquer thinner, just to get the cr*p off. Then use electrical termination cleaner on each brass terminal. I cleaned up a bunch of them with a dremel grinder, just enough to get the junk off. Or I reterminated and soldered as the factory had done (esp. the heavy gauge wires...)
If the old harness showed me the length, I terminated new connectors there, if not, I left it a bit long to allow for in-car clean up.
Registered User
Joined: Nov 2012
Posts: 34
From: Ajax, Ontario
Sounds like a great job. Did you take any pictures along the way? And any particular places where you got new connectors? I am looking for some myself to replace some or/and tidy up some previously done c*****y jobs 
Thread Starter
Registered User
Joined: May 2009
Posts: 2,179
From: Northern California
I'll write up a proper post at some point, but the key unusual parts supplier was these guys: http://www.clipsandfasteners.com
PS: Old Oldsmobiles have _lots_ of electrical connections! But you can reuse the plastic shells over new terminations, so the shells are really optional.
PS: Old Oldsmobiles have _lots_ of electrical connections! But you can reuse the plastic shells over new terminations, so the shells are really optional.
Registered User
Joined: Nov 2012
Posts: 34
From: Ajax, Ontario
[QUOTE=cfair;694107]I'll write up a proper post at some point, but the key unusual parts supplier was these guys: http://www.clipsandfasteners.com
Good site to know for sure. Too bad I am getting killed with shipping by being in Canada.
Good site to know for sure. Too bad I am getting killed with shipping by being in Canada.
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