Random wire unplugged under dash what is it where does it go? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

**kna4977** · 09-13-2024, 06:44 PM

Have a green wire that looks newer than the rest of the wires hanging under the dash near the fuse panel. The only terminal I see on the panel without anything attached is the back up light prong. Is this wire for that?

**Stocker** · 09-13-2024, 07:22 PM

I don't see a wire like that on my '72. Do your backup lights work? If not, try connecting it to a hot terminal and see if the backup lights come on.

**kna4977** · 09-13-2024, 07:38 PM

Quote:

Originally Posted by Stocker

I don't see a wire like that on my '72. Do your backup lights work? If not, try connecting it to a hot terminal and see if the backup lights come on.

They do so I’m not sure what it is or is for.

**dmjlambert** · 09-13-2024, 07:41 PM

I don't agree. I would not just connect it to power without knowing for a fact where it goes. I recommend finding out for sure what is on the other end of the wire. Dig or hire somebody to dig.

**kna4977** · 09-13-2024, 07:51 PM

Quote:

Originally Posted by dmjlambert

I don't agree. I would not just connect it to power without knowing for a fact where it goes. I recommend finding out for sure what is on the other end of the wire. Dig or hire somebody to dig.

I agree just wanted to see if anyone else had this random unplugged wire. It’s odd because the wiring harness is original and not butchered at all yet this random newer looking green wire is hanging there. I was thinking it may have been detached from where it was plugged by foot or pedal movement given its proximity to the pedals but not sure.

**PbFut** · 09-13-2024, 08:56 PM

It is possible it was kicked loose, or unplugged by PO when whatever it was for removed prior to sale. The opposite end may not be insolated and cause issue if you just try and plug in. Find the termination first. Then decide if its worth leaving in place. Looks in good condition and might come in handy someday.

**Steeveedee** · 09-13-2024, 11:38 PM

Doesn't look stock to me, but you can go here and look at the manuals for your year truck for that color of wire-

https://67-72chevytrucks.com/vboard/...ghlight=hatzie

**Stocker** · 09-14-2024, 12:22 AM

Is there anything electrical on the truck that isn't working?

lil hoodlum · 09-14-2024, 02:22 AM

Don't know about the green part of the wiring, but the connector terminal sure looks like the 12 V power wire to the factory radio.

In my photos it's the red wire that is the 12 V wire and connector plugged in to the other connector.

The other photo is the back of the radio wire the other connector plugs in to.

**'68OrangeSunshine** · 09-14-2024, 05:34 AM

OP: Is your Cigar Lighter working?

**1970cstblazer** · 09-14-2024, 07:18 AM

The factory cigar lighter wire is a 12 gauge red wire with a special plug on the lighter end.

Might be for TCS.

**'68OrangeSunshine** · 09-14-2024, 03:18 PM

Quote:

Originally Posted by 1970cstblazer

The factory cigar lighter wire is a 12 gauge red wire with a special plug on the lighter end.
.

The DeLuxe Cigar Lighter Socket has a piggyback courtesy lamp that clips into it. My aftermarket set had a Green line from that clip to power the illuminator.
Counterparts part, iirc. That by no means implies it's canon, but it's just a suggestion.

TCS is only on MY '71/'72 Trucks.

**kna4977** · 09-14-2024, 04:25 PM

Yes the lighter works. Not sure what TCS is. The green wire does route back to the lighter and is apparently used to tie into the dash lights so that it can illuminate with them. Comes on reproduction units like 68orangesunshine said above. I don't believe Blazers were available with illuminated cigar lighters. In fact I don't know what they would have come on as I've never seen an original one.

**1970cstblazer** · 09-16-2024, 09:04 AM

Quote:

Originally Posted by '68OrangeSunshine

The DeLuxe Cigar Lighter Socket has a piggyback courtesy lamp that clips into it. My aftermarket set had a Green line from that clip to power the illuminator.
Counterparts part, iirc. That by no means implies it's canon, but it's just a suggestion.

TCS is only on MY '71/'72 Trucks.

1970 also had TCS, and it's totally different than the two other years.

TCS is transmission controlled spark.

**damnyankee36** · 09-17-2024, 02:50 PM

That's a mystery! Light green is the color for backup lights along with probably one or two other functions. The backup lights feed wire is combined with the pink wire in an "L"-shaped double connector that connects to the neutral safety switch on top of the column if it is an automatic trans.

Surely, that's not it...

**Rust_never_sleeps** · 09-17-2024, 03:56 PM

I see three LG leads off the back of the fuse box on the 70 diagram(YMMV ;-) )

Notation in red is mine, ignore the 14R note
18ga to the backup light by way of the stop/tail harness
20ga to the high bean indicator light on the instrument cluster
16ga to the dimmer switch

Hope this helps

**'68OrangeSunshine** · 09-19-2024, 01:56 AM

Quote:

Originally Posted by damnyankee36

That's a mystery! Light green is the color for backup lights along with probably one or two other functions. The backup lights feed wire is combined with the pink wire in an "L"-shaped double connector that connects to the neutral safety switch on top of the column if it is an automatic trans.

Surely, that's not it...

We already found it.
Look at Post 13.
It's the lead for the illuminator bulb on the aftermarket [Counterpart, etc.] Cigar Lighter assembly. A bulb holder clips onto the socket, its ground is the socket, and the Green wire ties into the instrument lights so it dims with the dash.
Since its aftermarket -- maybe a mod from later years -- it won't be on the model year schematic
Mystery over.

09-13-2024, 06:44 PM	#1
kna4977 Senior Member Join Date: Jul 2006 Location: Midlothian TX Posts: 499	Random wire unplugged under dash what is it where does it go? Have a green wire that looks newer than the rest of the wires hanging under the dash near the fuse panel. The only terminal I see on the panel without anything attached is the back up light prong. Is this wire for that? Attached Images

09-13-2024, 07:22 PM	#2
Stocker 20' Daredevil (Ret) Join Date: May 2003 Location: Jefferson State Posts: 13,731	Re: Random wire unplugged under dash what is it where does it go? I don't see a wire like that on my '72. Do your backup lights work? If not, try connecting it to a hot terminal and see if the backup lights come on. __________________ - Mike - 1972 K20 LWB 350/350/205 RIP El Jay

09-13-2024, 07:41 PM	#4
dmjlambert Senior Member Join Date: Apr 2016 Location: Cypress, TX Posts: 3,894	Re: Random wire unplugged under dash what is it where does it go? I don't agree. I would not just connect it to power without knowing for a fact where it goes. I recommend finding out for sure what is on the other end of the wire. Dig or hire somebody to dig.

09-13-2024, 08:56 PM	#6
PbFut Senior Member Join Date: Feb 2022 Location: Ca Posts: 643	Re: Random wire unplugged under dash what is it where does it go? It is possible it was kicked loose, or unplugged by PO when whatever it was for removed prior to sale. The opposite end may not be insolated and cause issue if you just try and plug in. Find the termination first. Then decide if its worth leaving in place. Looks in good condition and might come in handy someday.

09-13-2024, 11:38 PM	#7
Steeveedee Who Changed This? Join Date: Jan 2013 Location: Simi Valley, CA Posts: 10,747	Re: Random wire unplugged under dash what is it where does it go? Doesn't look stock to me, but you can go here and look at the manuals for your year truck for that color of wire- https://67-72chevytrucks.com/vboard/...ghlight=hatzie __________________ ~Steven '70 Chevy 3/4T Longhorn CST 402/400/3.56 Custom Camper Simi Valley, CA

09-14-2024, 12:22 AM	#8
Stocker 20' Daredevil (Ret) Join Date: May 2003 Location: Jefferson State Posts: 13,731	Re: Random wire unplugged under dash what is it where does it go? Is there anything electrical on the truck that isn't working? __________________ - Mike - 1972 K20 LWB 350/350/205 RIP El Jay

09-14-2024, 02:22 AM	#9
lil hoodlum Registered User Join Date: Oct 2009 Location: Denton, Texas Posts: 1,735	Re: Random wire unplugged under dash what is it where does it go? Don't know about the green part of the wiring, but the connector terminal sure looks like the 12 V power wire to the factory radio. In my photos it's the red wire that is the 12 V wire and connector plugged in to the other connector. The other photo is the back of the radio wire the other connector plugs in to. Attached Images __________________ 1968 C10 327, 3 speed manual, LWB stock height daily driver. 1968 C20 327, 4 speed manual, LWB stock height custom camper with heavy duty leaf springs rear, 50th anniversary edition. Hoping to press into daily drive status soon.

09-14-2024, 05:34 AM	#10
'68OrangeSunshine Senior Member Join Date: Feb 2002 Location: Tucson, AZ USA Posts: 7,536	Re: Random wire unplugged under dash what is it where does it go? OP: Is your Cigar Lighter working? __________________ Every 25 years I like to rebuild that 292, whether it needs it or not.

09-14-2024, 07:18 AM	#11
1970cstblazer All stock and staying that way Join Date: Jul 2003 Location: Elkland, PA Posts: 1,894	Re: Random wire unplugged under dash what is it where does it go? The factory cigar lighter wire is a 12 gauge red wire with a special plug on the lighter end. Might be for TCS. __________________ 1970 K/5 Blazer CST 4WD, TOTM winner December 2024! Medium Bronze, 93k ACT. miles, 350, 4 speed, rear positraction, 16.5" x 8.25" HD wheel option, tilt, tach, vacuum, AM/FM, manual throttle...Dad ordered and purchased new 4/70. Currently frame off restoration finally getting close to completion.. 1972 Cheyenne Super 20 2WD, DK Blue/White, 90K ACT. miles, 402, TH400, 4.10 open, tilt, tach, vacuum, A/C, AM/FM, manual throttle.. A mostly original paint never rusted Texas survivor... 2017 Sierra 1500 SLT 4WD, Black, 45k miles, 5.3, 6L80E, 3.42 LS, 20" polished wheels, everything but moonroof and 6.2... 2019 Canyon SLT 4WD, White, 62k miles, 3.6, 8L45, 3.23 LS, 18" wheels

09-14-2024, 04:25 PM	#13
kna4977 Senior Member Join Date: Jul 2006 Location: Midlothian TX Posts: 499	Re: Random wire unplugged under dash what is it where does it go? Yes the lighter works. Not sure what TCS is. The green wire does route back to the lighter and is apparently used to tie into the dash lights so that it can illuminate with them. Comes on reproduction units like 68orangesunshine said above. I don't believe Blazers were available with illuminated cigar lighters. In fact I don't know what they would have come on as I've never seen an original one.

09-17-2024, 02:50 PM	#15
damnyankee36 Senior Member Join Date: Sep 2002 Location: Alamogordo, NM Posts: 724	Re: Random wire unplugged under dash what is it where does it go? That's a mystery! Light green is the color for backup lights along with probably one or two other functions. The backup lights feed wire is combined with the pink wire in an "L"-shaped double connector that connects to the neutral safety switch on top of the column if it is an automatic trans. Surely, that's not it... __________________ 1966 C10 Custom Cab Restomod (Sold) 1969 Camaro Z/28 (Keeper) Current Build: 1968 C10 (Semi-Factory Restoration) 1983 Camaro Z/28 (Next in line, Keeper) 1951 3100 (2nd in line)

09-17-2024, 03:56 PM	#16
Rust_never_sleeps Senior Member Join Date: Jun 2022 Location: San Ramon,CA Posts: 625	Re: Random wire unplugged under dash what is it where does it go? I see three LG leads off the back of the fuse box on the 70 diagram(YMMV ;-) ) Notation in red is mine, ignore the 14R note 18ga to the backup light by way of the stop/tail harness 20ga to the high bean indicator light on the instrument cluster 16ga to the dimmer switch Hope this helps Attached Images __________________ 1970 C10 Custom longbed 350/350 Code: __ ______\|__]\____ ....\|___(o)_____(o)_]



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