New wiring harness help - The 1947 - Present Chevrolet & GMC Truck Message Board Network

**425HP409** · 01-11-2024, 07:14 PM

I installed a 396 in place of the original small block. The new engine wiring harness has this pink wire in the harness near the left temp sender. I can’t figure what it is for as the green temp sender wire is there for the sender.
ps: the photo reversed itself.

steveo70 · 01-12-2024, 08:36 AM

On my American Autowire kit, the pink wire was for the HEI distributor I used.

IIGW · 01-12-2024, 11:00 AM

Quote:

Originally Posted by steveo70

the pink wire was for the HEI distributor I used.

yessir

since the dawn of time the pink should be power to distributor.

check it with a testlight

**pjmoreland** · 01-12-2024, 12:00 PM

That's not the right kind of connector for HEI. If you ordered a harness for a truck with A/C, then that wire may be for a carb-mounted idle stop solenoid that bumps up the engine RPM when the A/C compressor is engaged.

**71CHEVYSHORTBED402** · 01-12-2024, 12:06 PM

What Moreland said. Though I thought it was for a anti-dieseling. Regardless, I cut it off. The connector for HEI is white.

**kwmech** · 01-12-2024, 01:38 PM

Don't cut it off directly. Follow it back to the bulkhead connector and remove the wire there

**425HP409** · 01-12-2024, 05:19 PM

Thanks for the info, I will check to see when it has power. It is too short to reach back to the HEI. It comes out of the loom between #3 and #5 cylinder, so I am leaning to a carb solenoid. I will report back.

**dmjlambert** · 01-12-2024, 06:57 PM

Another thing to get switched power in the area of the carburetor is carburetor-mounted TH400 transmission kickdown switch. I would think the manufacturer of the new wiring harness should be able to tell exactly what they intended you to use that plug for.

**MikeB** · 01-13-2024, 04:25 PM

Quote:

Originally Posted by 71CHEVYSHORTBED402

What Moreland said. Though I thought it was for a anti-dieseling. Regardless, I cut it off. The connector for HEI is white.

White is the tach feed, unless the truck's wiring has been messed with by a previous owner.

I would not suggest cutting off a connector unless you are absolutely sure you'll never need it.

RustyPile · 01-15-2024, 05:17 AM

A good rule of thumb when installing aftermarket products.. When all else fails, read the instruction manual.. In other words, contact the manufacturer..

71 super · 01-16-2024, 11:08 AM

The Pink wire is for the fast idle solenoid located at the front of the carb. It is the single spade plug- pink wire, purpose is to kick up fast idle when A/C is running. It is shrouded in the asphalt loom to protect from heat generated on intake manifold. The correct solenoid /bracket and screw can be a difficult find if missing. There is a an aftermarket delco type that is shorter but serves the same function. it may also have the bracket as well. The plunger is adjusted via the nut at the head of the solenoid to increase rpm at idle a few 100 rpm while air is on.

**MikeB** · 01-16-2024, 06:06 PM

Quote:

Originally Posted by 71 super

The Pink wire is for the fast idle solenoid located at the front of the carb.

I forgot about that! They're also available for Holley and Edelbrock carbs, but are ridiculously expensive.

**damnyankee36** · 01-17-2024, 03:35 PM

I had the same question a couple of months ago.

https://67-72chevytrucks.com/vboard/...d.php?t=848442

The original harness had the same connector. The truck was already partially torn apart so I couldn't verify where it went to. As suggested by others it could be used as an idle stop solenoid, but not for the AC kickup as it's always powered when the engine is running. I don't know why such a large gauge wire would be needed for that function.

It is connected to the same terminal at the firewall bulkhead connector as the coil resistor wire. My plan is to cut open that part of the harness and reroute it for use with the HEI.

**425HP409** · 01-18-2024, 05:20 PM

I checked it and it has key on power and will reach to the carb where an anti dieseling solenoid would have been installed. Now I have an extra power lead if I ever need one.

**damnyankee36** · 01-18-2024, 05:23 PM

Just remember, it's unfused.

**425HP409** · 01-19-2024, 12:37 PM

Quote:

Originally Posted by damnyankee36

Just remember, it's unfused.

Thanks...

**71CHEVYSHORTBED402** · 01-23-2024, 11:26 AM

Quote:

Originally Posted by MikeB

White is the tach feed, unless the truck's wiring has been messed with by a previous owner.

I would not suggest cutting off a connector unless you are absolutely sure you'll never need it.

You're right, I should be careful. Harnesses vary by year and requirements. My replacement engine harness for HEI is 12 AWG pink wire with a white connector, runs from IGN to BAT. I'm 80/20 the wire on topic is for anti-dieseling. Make that 70/30

Good thing I didn't need it. Mine had to route to the RH side for a temp sender, because the plug in the LH head is frozen for a BBC, didn't prepare for that. The harness' layout ends up cleaner, though I may? have requested a longer temperature wire.

Quote:

Originally Posted by 425HP409

I checked it and it has key on power and will reach to the carb where an anti dieseling solenoid would have been installed. Now I have an extra power lead if I ever need one.

Great. Now I'm 98/2 it's for anti-dieseling

I'd like to see one set up, but can't find it.

schovil69 · 01-26-2024, 06:13 PM

I used that wire for an electric choke.

**425HP409** · 01-27-2024, 12:04 PM

Quote:

Originally Posted by schovil69

I used that wire for an electric choke.

That is a good use for it.

01-11-2024, 07:14 PM	#1
425HP409 425hp409 Join Date: Oct 2008 Location: Prosper Texas Posts: 834	New wiring harness help I installed a 396 in place of the original small block. The new engine wiring harness has this pink wire in the harness near the left temp sender. I can’t figure what it is for as the green temp sender wire is there for the sender. ps: the photo reversed itself. Attached Images __________________ Charles 68 SWB, Dad bought new, now 396 & factory ac 64 Impala SS, 409 425HP, 4 speed AC 64 Bel Air Wagon, 400 Small Block 57 Bel Air all original 283 w/Factory Air 77 GMC Sprint, 454/425HP 67 Olds 442, all original 90 ZR1 Corvette

01-12-2024, 08:36 AM	#2
steveo70 Registered User Join Date: May 2015 Location: st louis missouri Posts: 26	Re: New wiring harness help On my American Autowire kit, the pink wire was for the HEI distributor I used.

01-12-2024, 12:00 PM	#4
pjmoreland Senior Member Join Date: Jan 2005 Location: CA Posts: 5,329	Re: New wiring harness help That's not the right kind of connector for HEI. If you ordered a harness for a truck with A/C, then that wire may be for a carb-mounted idle stop solenoid that bumps up the engine RPM when the A/C compressor is engaged.

01-12-2024, 01:38 PM	#6
kwmech Senior Member Join Date: Mar 2003 Location: Colfax-California Posts: 8,391	Re: New wiring harness help Don't cut it off directly. Follow it back to the bulkhead connector and remove the wire there

01-12-2024, 05:19 PM	#7
425HP409 425hp409 Join Date: Oct 2008 Location: Prosper Texas Posts: 834	Re: New wiring harness help Thanks for the info, I will check to see when it has power. It is too short to reach back to the HEI. It comes out of the loom between #3 and #5 cylinder, so I am leaning to a carb solenoid. I will report back. __________________ Charles 68 SWB, Dad bought new, now 396 & factory ac 64 Impala SS, 409 425HP, 4 speed AC 64 Bel Air Wagon, 400 Small Block 57 Bel Air all original 283 w/Factory Air 77 GMC Sprint, 454/425HP 67 Olds 442, all original 90 ZR1 Corvette

01-12-2024, 12:06 PM	#5
71CHEVYSHORTBED402 Senior Member Join Date: Feb 2009 Location: Northern Nevada Posts: 7,120	Re: New wiring harness help What Moreland said. Though I thought it was for a anti-dieseling. Regardless, I cut it off. The connector for HEI is white. __________________ Tony 71 Custom Deluxe, SWB, 2WD, 402, A/C. I developed an assm. guide "kit" for restoring it from ground up. With assys, the guide accts for 1000s of OEM identifications and part numbers, all written in short order. 700+ images include assm, illust., charts, and points of interest. Much of the info. applies to all 67-72 GM trucks, and to a lessor degree all 67-72 GM vehicles. My build thread, and more on the guide https://67-72chevytrucks.com/vboard/...d.php?t=730025

01-12-2024, 06:57 PM	#8
dmjlambert Senior Member Join Date: Apr 2016 Location: Cypress, TX Posts: 3,564	Re: New wiring harness help Another thing to get switched power in the area of the carburetor is carburetor-mounted TH400 transmission kickdown switch. I would think the manufacturer of the new wiring harness should be able to tell exactly what they intended you to use that plug for.

01-15-2024, 05:17 AM	#10
RustyPile Registered User Join Date: Dec 2017 Location: Elkhart, Texas Posts: 1,531	Re: New wiring harness help A good rule of thumb when installing aftermarket products.. When all else fails, read the instruction manual.. In other words, contact the manufacturer..

01-16-2024, 11:08 AM	#11
71 super Registered User Join Date: Sep 2005 Location: Canton North carolina Posts: 3,075	Re: New wiring harness help The Pink wire is for the fast idle solenoid located at the front of the carb. It is the single spade plug- pink wire, purpose is to kick up fast idle when A/C is running. It is shrouded in the asphalt loom to protect from heat generated on intake manifold. The correct solenoid /bracket and screw can be a difficult find if missing. There is a an aftermarket delco type that is shorter but serves the same function. it may also have the bracket as well. The plunger is adjusted via the nut at the head of the solenoid to increase rpm at idle a few 100 rpm while air is on. __________________ 67 blue step side- bb 68 gold and white swb cst anniversary 68 custom swb hot rod Ls swap 69 swb cst 6 cylinder/ overdrive 69 black/black cst bb swb 70 orange and white cst Canada built truck swb bb 71 black and white super swb bb 71 red and white super swb 72 green and white super swb 4x4 62 nova wagon 400 series Ls swapped 68 Camaro 327/4 speed- 1 owner, original paint 66 Volkswagen bettle 69 auto stick Volkswagen Beetle

01-17-2024, 03:35 PM	#13
damnyankee36 Senior Member Join Date: Sep 2002 Location: Alamogordo, NM Posts: 677	Re: New wiring harness help I had the same question a couple of months ago. https://67-72chevytrucks.com/vboard/...d.php?t=848442 The original harness had the same connector. The truck was already partially torn apart so I couldn't verify where it went to. As suggested by others it could be used as an idle stop solenoid, but not for the AC kickup as it's always powered when the engine is running. I don't know why such a large gauge wire would be needed for that function. It is connected to the same terminal at the firewall bulkhead connector as the coil resistor wire. My plan is to cut open that part of the harness and reroute it for use with the HEI. __________________ 1966 C10 Custom Cab Restomod (Sold) 1969 Camaro Z/28 1983 Camaro Z/28 Current Build: 1968 C10 (Semi-Factory Restoration)

01-18-2024, 05:20 PM	#14
425HP409 425hp409 Join Date: Oct 2008 Location: Prosper Texas Posts: 834	Re: New wiring harness help I checked it and it has key on power and will reach to the carb where an anti dieseling solenoid would have been installed. Now I have an extra power lead if I ever need one. __________________ Charles 68 SWB, Dad bought new, now 396 & factory ac 64 Impala SS, 409 425HP, 4 speed AC 64 Bel Air Wagon, 400 Small Block 57 Bel Air all original 283 w/Factory Air 77 GMC Sprint, 454/425HP 67 Olds 442, all original 90 ZR1 Corvette

01-18-2024, 05:23 PM	#15
damnyankee36 Senior Member Join Date: Sep 2002 Location: Alamogordo, NM Posts: 677	Re: New wiring harness help Just remember, it's unfused. __________________ 1966 C10 Custom Cab Restomod (Sold) 1969 Camaro Z/28 1983 Camaro Z/28 Current Build: 1968 C10 (Semi-Factory Restoration)

01-26-2024, 06:13 PM	#18
schovil69 Registered User Join Date: Oct 2013 Location: Lincoln, NE Posts: 115	Re: New wiring harness help I used that wire for an electric choke.



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