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73-87 Chevy _ GMC Trucks => Electrical => Topic started by: MY1978 on April 30, 2021, 04:30:47 pm

Title: Mystery Wire
Post by: MY1978 on April 30, 2021, 04:30:47 pm
I have this wire that has not home.  Was wondering if anyone might know what it would go to.  I used to have an 8-track player, many years ago, then a cassette player.  Both are gone.  The first picture is of the connection end, the second is where it connects/splices into a orange wire, and the 3rd pic is where the orange wire connects into the fuse block.

Can anyone provide some insight or have seen this before?

Thanks.
Title: Re: Mystery Wire
Post by: bd on April 30, 2021, 04:54:51 pm
The orange pigtail is fused battery power.  The blue extension was probably for a long-ago disconnected aftermarket accessory.  The "connector" on the free end looks like one-half of an inline fuse holder.
Title: Re: Mystery Wire
Post by: MY1978 on April 30, 2021, 06:38:32 pm
The orange pigtail is fused battery power.  The blue extension was probably for a long-ago disconnected aftermarket accessory.  The "connector" on the free end looks like one-half of an inline fuse holder.

So, since it is very apparently not powering anything, it would be safe to disconnect at the connection point where the blue and orange come together?
Title: Re: Mystery Wire
Post by: bd on April 30, 2021, 10:17:00 pm
That's what I would do.
Title: Re: Mystery Wire
Post by: MY1978 on May 01, 2021, 07:40:36 pm
Done!  Thanks.  i have disconnected the blue completely and wrap electrical tape around it.  I will do the same for the mysterious double pink wires that are currently unplugged from the block and have not affected anything. 
Title: Re: Mystery Wire
Post by: bd on May 01, 2021, 08:11:39 pm
FYI - the pink wires are fused ignition power taps.
Title: Re: Mystery Wire
Post by: MY1978 on May 02, 2021, 01:20:57 am
Thanks bd.  They are plugged in in that picture, but currently unplugged and nothing has been affected by that.  Why would they be plugged in if nothing is needed by them? 
Title: Re: Mystery Wire
Post by: bd on May 02, 2021, 01:19:09 pm
Where do the other ends of those pink wires go?  Are they hanging free?  Do they disappear into a taped harness?  The blue connector looks original to the truck and the factory doesn't install wires for no reason.  It's up to you to determine whether they are relevant at this point in time.
Title: Re: Mystery Wire
Post by: MY1978 on May 02, 2021, 02:25:39 pm
Yep, a single pink goes into a taped harness.  The lower pink one has a paper tag on it.  Looks like it says 1216.  The blue wire in in pic is for my trailering electric brake set up.

Sent from my LM-V600 using Tapatalk
Title: Re: Mystery Wire
Post by: Mike81K10 on May 02, 2021, 06:36:10 pm
Don't like the way that bare wire looks coming out the connector. I would put a new terminal on it or at a minimum some heat shrink. Need to cover it.
Title: Re: Mystery Wire
Post by: MY1978 on May 02, 2021, 06:58:17 pm
Yeah, I have been concerned with that.  Here is a picture of the fuse block when the pink wire connector was plugged in.  As you can see, the end connector is not connected to anything.  If I had to make a guess, I think it is an original wiring due to the paper tag on it.  What is the 1216 number?.  I just do not know what it is supposed to power.  Everything is working fine.  I did have a headlight warning buzzer when I bought the truck, and that came up missing.  I just recently installed a new one.  Since it is currently not connect to the fuse block and just floating out there and everything seems to working fine, I was thinking of just removing the connector where the exposed wire is, add a wire nut and some tape and be done with it.    Unless someone thinks this is a bad idea.

Sent from my LM-V600 using Tapatalk

Title: Re: Mystery Wire
Post by: Mike81K10 on May 02, 2021, 11:26:25 pm
Take a look at the wiring diagram from this forum at this link:
http://www.73-87chevytrucks.com/techinfo/wiring_diagrams/73-76_instrument.jpg

I was a little confused the way your Fuse Box looked for a 1978. The diagram is from a 73-76 and it appears will help you out. The 18P-139A shows two pink (P) wires connected and looks like it goes to tach. Do you have a tach on your truck? This forum has diagrams you can use to track down your wires. You can also access the repair manual for your model truck
Title: Re: Mystery Wire
Post by: VileZambonie on May 03, 2021, 06:23:16 am
Looks like an aftermarket power tap for your brake controller. I'd get rid of all of it including the scotch locks.
Title: Re: Mystery Wire
Post by: MY1978 on May 03, 2021, 06:54:05 am
Take a look at the wiring diagram from this forum at this link:
http://www.73-87chevytrucks.com/techinfo/wiring_diagrams/73-76_instrument.jpg

I was a little confused the way your Fuse Box looked for a 1978. The diagram is from a 73-76 and it appears will help you out. The 18P-139A shows two pink (P) wires connected and looks like it goes to tach. Do you have a tach on your truck? This forum has diagrams you can use to track down your wires. You can also access the repair manual for your model truck

Yes, My little truck is a hybrid of '77 & '78, metric and SAE.  I think they were trying to get rid of some of the '77 stuff and I was the lucky recipient.  Oh what fun it has been to figure things out......which is why I really appreciate all the help you guys have given me and not just brushed me off as some dumb woman that doesn't need to know.

This truck is stock, it has never had a tach.  I have a fuel gauge where I have seen most tach.

Title: Re: Mystery Wire
Post by: MY1978 on May 03, 2021, 06:57:44 am
Looks like an aftermarket power tap for your brake controller. I'd get rid of all of it including the scotch locks.

Thinking back, I believe I had a different brake controller than the one I have.  I would be happy to get rid of this.  Since it goes into the wiring harness, and I have never had a tach and I believe a different brake controller, would the best solution be to just disconnect the pink wire going up into the harness at the 1st scotch lock, cap it and tape it in case it might be needed in the future?
Title: Re: Mystery Wire
Post by: MY1978 on May 03, 2021, 07:34:16 am
I found this wiring diagram (WHERE do I find one for my very own???) that shows the cruise control (which I have) has a double pink wire connection that plugs into the fuse block as a fused ignition.  Since I have not been able to drive the truck due to cab restoration, I have not been able to test this.  So, until I do, I think I will leave it alone for now and actually fix the exposed wires issue.  Stay tuned, this story isn't over yet!   :)
Title: Re: Mystery Wire
Post by: Mike81K10 on May 03, 2021, 02:53:44 pm
That is the same as the wiring diagram I gave you a reference to on the forum. It is more of a compact version without the other wiring.
Title: Re: Mystery Wire
Post by: MY1978 on May 04, 2021, 05:58:40 am
That is the same as the wiring diagram I gave you a reference to on the forum. It is more of a compact version without the other wiring.

Yep Mike and thanks for sending that.  I am far from being a wire guru, learning as I go which I why I have posted stuff along the journey of the restoration.  This one was easier to understand and also shows the double pink fused connection at the fuse block.

But again, thanks for sending.   :)
Title: Re: Mystery Wire
Post by: MY1978 on May 05, 2021, 07:48:11 pm
Don't like the way that bare wire looks coming out the connector. I would put a new terminal on it or at a minimum some heat shrink. Need to cover it.

Hey Mike, you will be happy to know that I took care of the bare wire situation.    ;)