Mystery Pink Wire in Engine Compartment - The 1947 - Present Chevrolet & GMC Truck Message Board Network

**damnyankee36** · 11-02-2023, 08:42 PM

When I disassembled this 68 there was a 12ga wire with a Packard connector on the end. It ran along the top of the driver side of the engine. The entire engine bay harness was a mess and this connector was just hanging.

It comes out of the firewall bulkhead at the same cavity as the coil resistor wire which means it's an ignition circuit. BTW, the new harness has the same wire. None of the diagrams I have seen show this wire.

Any ideas?

**Steeveedee** · 11-02-2023, 10:15 PM

Could be the HEI ignition power wire. That won't show up on our older wiring diagrams.

**damnyankee36** · 11-02-2023, 10:47 PM

Thanks.

While this would make a good power source for an HEI, it doesn't need to be this long for that. Keep in mind this wire is also on the original harness.

**Rust_never_sleeps** · 11-03-2023, 12:31 AM

fuel gauge?

**Rust_never_sleeps** · 11-03-2023, 12:42 AM

better view here:
https://drive.google.com/file/d/130h...VyR/view?pli=1

**71CHEVYSHORTBED402** · 11-03-2023, 01:23 AM

Quote:

Originally Posted by damnyankee36

When I disassembled this 68 there was a 12ga wire with a Packard connector on the end. It ran along the top of the driver side of the engine. The entire engine bay harness was a mess and this connector was just hanging.

It comes out of the firewall bulkhead at the same cavity as the coil resistor wire which means it's an ignition circuit. BTW, the new harness has the same wire. None of the diagrams I have seen show this wire.

Any ideas?

I wonder if that's for anti-dieseling, which is on the engine harness. My eyes say it's pink. I've yet to see one mounted. Your truck have A/C?

Seems 71-72 AC cabs had an anti-dieseling relay mounted to the dash, and a mystery part located somewhere under the hood.

Come to think of it, here's an 1971 M&H engine harness built for an HEI distributor. They throw all kinds of wires at it, modify as you need to.

**70STOVEBOLT** · 11-03-2023, 07:14 AM

It's for an idle stop solenoid. Should be hot with key on.

**damnyankee36** · 11-06-2023, 07:46 PM

That sounds logical, although that's a big wire just for a solenoid. The truck does have factory AC but there wasn't a solenoid installed on the carb when I tore it down.

No matter, it's getting EFI so I'll save it for another possible function.

Thanks for the help guys.

**damnyankee36** · 11-06-2023, 07:48 PM

Quote:

Originally Posted by 71CHEVYSHORTBED402

I wonder if that's for anti-dieseling, which is on the engine harness. My eyes say it's pink. I've yet to see one mounted. Your truck have A/C?

Thanks, see my response above.

11-02-2023, 08:42 PM	#1
damnyankee36 Senior Member Join Date: Sep 2002 Location: Alamogordo, NM Posts: 724	Mystery Pink Wire in Engine Compartment When I disassembled this 68 there was a 12ga wire with a Packard connector on the end. It ran along the top of the driver side of the engine. The entire engine bay harness was a mess and this connector was just hanging. It comes out of the firewall bulkhead at the same cavity as the coil resistor wire which means it's an ignition circuit. BTW, the new harness has the same wire. None of the diagrams I have seen show this wire. Any ideas? Attached Images

11-02-2023, 10:15 PM	#2
Steeveedee Who Changed This? Join Date: Jan 2013 Location: Simi Valley, CA Posts: 10,708	Re: Mystery Pink Wire in Engine Compartment Could be the HEI ignition power wire. That won't show up on our older wiring diagrams. __________________ ~Steven '70 Chevy 3/4T Longhorn CST 402/400/3.56 Custom Camper Simi Valley, CA

11-02-2023, 10:47 PM	#3
damnyankee36 Senior Member Join Date: Sep 2002 Location: Alamogordo, NM Posts: 724	Re: Mystery Pink Wire in Engine Compartment Thanks. While this would make a good power source for an HEI, it doesn't need to be this long for that. Keep in mind this wire is also on the original harness.

11-03-2023, 12:31 AM	#4
Rust_never_sleeps Senior Member Join Date: Jun 2022 Location: San Ramon,CA Posts: 599	Re: Mystery Pink Wire in Engine Compartment fuel gauge? Attached Images

11-03-2023, 12:42 AM	#5
Rust_never_sleeps Senior Member Join Date: Jun 2022 Location: San Ramon,CA Posts: 599	Re: Mystery Pink Wire in Engine Compartment better view here: https://drive.google.com/file/d/130h...VyR/view?pli=1

11-03-2023, 07:14 AM	#7
70STOVEBOLT Senior Member Join Date: Jun 2005 Location: Winona Lake, IN Posts: 6,422	Re: Mystery Pink Wire in Engine Compartment It's for an idle stop solenoid. Should be hot with key on. __________________ 70 C/10 SWB 402/TH400/3.73 "The Needy Beast" 200,000 Mile Club Disc Brake Club Owner installed options: Front Sway Bar Power Steering Power Brakes Cigar Lighter Courtesy Lights Deluxe Side Markers Wiper Delay Sliding Rear Window Power Windows Power Locks Sniper EFI 2015 Silverado 1500 LS 4.3/6L80/3.23 lowered 2" front & rear

11-06-2023, 07:46 PM	#8
damnyankee36 Senior Member Join Date: Sep 2002 Location: Alamogordo, NM Posts: 724	Re: Mystery Pink Wire in Engine Compartment That sounds logical, although that's a big wire just for a solenoid. The truck does have factory AC but there wasn't a solenoid installed on the carb when I tore it down. No matter, it's getting EFI so I'll save it for another possible function. Thanks for the help guys.

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