Engine wiring harness question - The 1947 - Present Chevrolet & GMC Truck Message Board Network

sodly · 10-14-2025, 12:54 PM

Can anyone tell me how to remove the wires from this engine harness plug (1966)? This is the plug that plugs into the firewall. How do you remove a wire from it? Do you need to stick something into the plug to release a tang? I have one wire that's developed a bare end that needs to be cleaned up. Probably will have to remove all of them from the plug to fix the one.

Anyone know what style of spade is on these wires that goes into that plug?

By the way, the problem wire is different than the others. It has sort of a metal braided coating, unlike the others that are colored plastic. Anyone know off hand what this wire does? The wiring diagram is unclear. This is a completely stock 327 truck.

Thanks!

**MusicMan70** · 10-14-2025, 03:09 PM

I read this over on the Electric section of the forum, but I'd ask there to be sure. Subject is a 69 truck so not directly applicable.

I'm sure VetteVet will know.

https://www.67-72chevytrucks.com/vbo...l+braided+WIRE

Quote:

Next is the cloth covered wire that started life as an orange/purple white wire that is a resistance wire to protect the ignition coil from overheating during normal running. It drops the ignition voltage to approximately 8 volts to the positive side of the coil. It joins a yellow wire which goes to the I terminal on the starter solenoid. This I terminal sends a full 12 volts to the coil during starting for a hotter spark while the engine is cranking.

sodly · 10-14-2025, 04:35 PM

Thanks, MusicMan70. Duh! Didn't even think to ask there.

ray_mcavoy · 10-14-2025, 06:11 PM

That connector uses Packard/Delphi (now Aptiv) 56-series terminals.

Here is a video showing how to remove them --> https://www.youtube.com/watch?v=beAQpdTXIgw

You'll be dealing with the male terminals on the engine side of the harness.

10-14-2025, 12:54 PM	#1
sodly Registered User Join Date: Nov 2009 Location: Nebraska Posts: 1,061	Engine wiring harness question Can anyone tell me how to remove the wires from this engine harness plug (1966)? This is the plug that plugs into the firewall. How do you remove a wire from it? Do you need to stick something into the plug to release a tang? I have one wire that's developed a bare end that needs to be cleaned up. Probably will have to remove all of them from the plug to fix the one. Anyone know what style of spade is on these wires that goes into that plug? By the way, the problem wire is different than the others. It has sort of a metal braided coating, unlike the others that are colored plastic. Anyone know off hand what this wire does? The wiring diagram is unclear. This is a completely stock 327 truck. Thanks! Attached Images __________________ WANTED: * 60-66 Chevy and GMC FACTORY PHOTOGRAPHY (scans) of pickups and carryalls. *Custom Camper Club*-- Own a 65-66 Custom Camper? Join us at: http://67-72chevytrucks.com/vboard/g...hp?groupid=117

10-14-2025, 04:35 PM	#3
sodly Registered User Join Date: Nov 2009 Location: Nebraska Posts: 1,061	Re: Engine wiring harness question Thanks, MusicMan70. Duh! Didn't even think to ask there. __________________ WANTED: * 60-66 Chevy and GMC FACTORY PHOTOGRAPHY (scans) of pickups and carryalls. *Custom Camper Club*-- Own a 65-66 Custom Camper? Join us at: http://67-72chevytrucks.com/vboard/g...hp?groupid=117

10-14-2025, 06:11 PM	#4
ray_mcavoy Registered User Join Date: Nov 2009 Location: Sherman, ME Posts: 2,404	Re: Engine wiring harness question That connector uses Packard/Delphi (now Aptiv) 56-series terminals. Here is a video showing how to remove them --> https://www.youtube.com/watch?v=beAQpdTXIgw You'll be dealing with the male terminals on the engine side of the harness.



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