Author Topic: What are these wires?  (Read 3667 times)

Offline 82apache

  • Newbie
  • Posts: 18
  • Newbie
What are these wires?
« on: December 23, 2019, 09:42:45 PM »
82 K20   Left of the brake booster and through the firewall, 2 wires 1 green and 1 pale yellow or white, stuck together like speaker wire. In the cab they appear to run up behind the instrument cluster, in the engine bay the other end dives into the plastic wire loom down by the frame that also houses the Rear Intermediate harness.

I don't have them on my '79 nor my '86.  Any clue as to what they are?

And Merry Christmas!

Online bd

  • Global Moderator
  • Senior Member
  • *****
  • Posts: 6438
Re: What are these wires?
« Reply #1 on: December 23, 2019, 11:13:47 PM »
Post a pic, please.
Rich
It's difficult to know just how much you don't know until you know it.
In other words... if people learn by making mistakes, by now I should know just about everything!!!
87 R10 Silverado Fleetside 355 MPFI 700R4 3.42 Locker (aka Rusty, aka Mater)

Offline 1984Texaswidebody

  • Newbie
  • Posts: 5
  • Newbie
Re: What are these wires?
« Reply #2 on: December 24, 2019, 04:40:42 AM »
Maybe the backup light and turn/hazard signal bulb.


Sent from my iPad using Tapatalk

Offline 82apache

  • Newbie
  • Posts: 18
  • Newbie
Re: What are these wires?
« Reply #3 on: December 24, 2019, 09:09:18 AM »
This morning a buddy of mine said it might be for the reverse switch. --700r4 

Does that ring a bell?   

Offline VileZambonie

  • Global Moderator
  • Senior Member
  • *****
  • Posts: 18979
Re: What are these wires?
« Reply #4 on: December 24, 2019, 12:09:56 PM »
No.

Sounds like something someone added, trailer brake etc.  but

Post a pic, please.
,                           ___ 
                         /  _ _ _\_
              ⌠ŻŻŻŻŻ'   [☼===☼]
              `()_);-;()_)--o--)_)

74 GMC, 75 K5, 84 GMC, 85 K20, 86 k20, 79 K10

Offline 82apache

  • Newbie
  • Posts: 18
  • Newbie
Re: What are these wires?
« Reply #5 on: December 25, 2019, 05:31:45 PM »
This is not a pic of mine but it appears to show the same wire combo.  The routing seems to be different as well but mine has been molested so that might account for that.  I am looking at a wire combo that has something to do with the fuel tanks?


The yellow-green combo roughly center of the pic

http://67-72chevytrucks.com/vboard/attachment.php?attachmentid=136170&stc=1&d=1113932884

Offline 82apache

  • Newbie
  • Posts: 18
  • Newbie
Re: What are these wires?
« Reply #6 on: December 25, 2019, 05:42:59 PM »
No.

Sounds like something someone added, trailer brake etc.  but

Post a pic, please.

I considered that however the plug/grommet thing where it comes through the firewall appears to be factory and there is no evidence that a brake controller was ever mounted to the dash.

Offline JohnnyPopper

  • Senior Member
  • ****
  • Posts: 2526
  • Old Goof
Re: What are these wires?
« Reply #7 on: December 26, 2019, 01:18:27 PM »
Flux Capacitor?  8)
1957 Apache 3100 235 Inline 6, 3 on the tree
1973 C-20, 3+3 454 4BBL TH400  Water Injection
1978 K-10, 350 4BBL TH350 NP203 M.M. Part time Kit/Hubs
1980 C-10 under construction

Offline 82apache

  • Newbie
  • Posts: 18
  • Newbie
Re: What are these wires?
« Reply #8 on: December 27, 2019, 01:53:17 AM »
Flux Capacitor?  8)

Hmm  I don't think so but with an old truck it is always hard to tell what all a PO has been doing with the wires. lol





Offline MIKE S

  • Registered Users
  • *
  • Posts: 224
  • Member
Re: What are these wires?
« Reply #9 on: December 27, 2019, 10:51:33 AM »
Do you have dual fuel tanks? That may be the harness for the sending unit.

Offline 82apache

  • Newbie
  • Posts: 18
  • Newbie
Re: What are these wires?
« Reply #10 on: January 03, 2020, 05:03:06 PM »
Do you have dual fuel tanks? That may be the harness for the sending unit.

I do have duel tanks.
Holidays have kept me busy so I have not had a chance to climb under and trace them but I am leaning toward that being it and for some odd reason having been rerouted by the PO into the rear intermediate harness loom. (any idea where they are supposed to run?)

The deeper in I get the more I think the wiring work was done by someone who almost, but not quite, knew what they were doing. lol  Local 2 bay shop with a crusty old Cooter type that knew how to make it work but was not very interested in actually doing it correctly, perhaps.

Offline 75gmck25

  • Frequent Member
  • **
  • Posts: 439
  • 1975 GMC K25 Camper Special, 350/TH350/NP203
Re: What are these wires?
« Reply #11 on: January 04, 2020, 06:07:45 AM »
Dual fuel tanks have a rubber plug and wires running through the firewall above the brake pedal area, but there should be at least 4 wires.  At least two of them should be tan or tan/white because that is the typical color of the sending unit wire.   

Bruce

Offline 1984Texaswidebody

  • Newbie
  • Posts: 5
  • Newbie
Re: What are these wires?
« Reply #12 on: January 04, 2020, 10:17:44 AM »



Sent from my iPad using Tapatalk

Offline 82apache

  • Newbie
  • Posts: 18
  • Newbie
Re: What are these wires?
« Reply #13 on: January 05, 2020, 12:16:00 AM »



Sent from my iPad using Tapatalk

Thanks but these wires are not actually part of the RIH, nor the Rear harness, they are just routed through the same wire loom tubing as the RIH.

The PO had spliced into the the RIH to power some sort of a power receptacle in the interior bed wall and in the process cut off both the plug at the end of the RIH and the plug at the beginning of the rear harness. The RIH and the RH are currently spliced together instead of plugged together and that is what got me started on this. I am replacing both harnesses and found the extra wires in the loom tube.

Offline 82apache

  • Newbie
  • Posts: 18
  • Newbie
Re: What are these wires?
« Reply #14 on: January 05, 2020, 12:31:23 AM »
Dual fuel tanks have a rubber plug and wires running through the firewall above the brake pedal area, but there should be at least 4 wires.  At least two of them should be tan or tan/white because that is the typical color of the sending unit wire.   

Bruce

OK, Looking from the grill,  these come trough the firewall through a rubber plug located to the left of the brake booster and through the right side of the engine indent. Only two wires and those fused together like speaker wire is.  It all looks factory and it does not appear that there was ever any other wires breaching the firewall through that plug.

The weather will be too wet to crawl under for the next few days, I will see if I can get a good pic tomorrow.