The 1947 - Present Chevrolet & GMC Truck Message Board Network

Register or Log In To remove these advertisements.

Go Back   The 1947 - Present Chevrolet & GMC Truck Message Board Network > 47 - Current classic GM Trucks > The 1973 - 1987 Chevrolet & GMC Squarebody Pickups Message Board


Thread Tools Display Modes
Old 09-05-2019, 05:10 PM   #1
Registered User
xs-style's Avatar
Join Date: Mar 2008
Location: Lawndale, NC
Posts: 641
87 wiring

Does anyone know of any suppliers that sell factory replacement harnesses for everything from the fire wall forward on an 87?
1978 Scottsdale - celebrating 10 years of teaching me profanity
1990 Silverado - bought in Nov. 2016 and it's already catching up - Sold
1987 k5 blazer - sold... :\ seed money for the 81
1981 k20 4x4 - 5.3 swap in progress

Events attended:
Spring GOG 2011
Dale JR car show Summer 2012
Gathering at Tommys pickup parts
xs-style is offline   Reply With Quote
Old 09-06-2019, 03:51 PM   #2
Registered User
MikeB's Avatar
Join Date: Jul 2000
Location: Plano, TX
Posts: 2,114
Re: 87 wiring

American Autowire sells a stock replacement engine harness. I'm not sure if that gets you the lighting harness. Give them a call, they are very helpful and their products are first rate. They are Number 1 or 2 on my all-time favorite vendor list.
82 C10 Custom Deluxe SWB -- original paint, 355/TH350, Vortec heads, GM RamJet 350 roller cam.
69 C10 LWB -- Bought in 1989, now my son's.
Retired as a factory automation products salesman.
Worked part-time over the years for an engine builder and a classic car repair shop.
Member here for 19 years! This is the very first car/truck Internet forum I joined.
MikeB is offline   Reply With Quote
Old 09-12-2019, 12:30 PM   #3
Registered User
Join Date: Feb 2007
Location: Central Florida
Posts: 160
Re: 87 wiring

I got a factory style firewall forward light harness from gmachinz on here. All the wire/sockets look like/are the factory style.

I would hit him up and see if he can make what you are looking for.
Nachos82 is offline   Reply With Quote
Old 09-14-2019, 11:30 AM   #4
Senior Member
hatzie's Avatar
Join Date: Oct 2008
Location: Wentworth, NH
Posts: 3,713
Re: 87 wiring

There are several harnesses and parts of harnesses that terminate at the firewall in the engine bay.
By 1987 they were complex enough that the one-size-fits-all harnesses weren't really useful. IMHO

Forward lamps and horn.
Engine sensors and ignition.
Main power.
Fuel and fuel level.
NL2 dual tanks if equipped.
Transmission TCC and or kickdown.
Rear lamps.
If I'm repairing a rear lamp harness I add a 12ga Blue Trailer brake and 12ga Orange trailer battery wires to the four lamp wires and I upgrade the earlier molded connector to the square 2x2 four position Weatherpak that GM used on the 1984 and newer trucks.

How bad is the original harness? Wire jacket cracks and such?

I usually separate the sub-harness in need of TLC from the chassis and lay it out on a sheet of plywood on sawhorses
Once it's laid out I replace the damaged wire or damaged terminal with a new wire and terminals. Do this one at a time with the same or adjusted length of new SXL wire & brand new Delphi (Aptiv Automotive now) terminals.
I replace the wire covering with new pieces where needed. The tape is harness tape not electrical tape. Black split poly loom is easily available from NAPA in shorter lengths along with 100' and 250' spools. I try to be fairly careful of the wiring clips and poly loom Tees and such as I don't have a decent supplier for small quantities, less than 5,000 or 10,000 order size, of these.
I try to re-use the original Delphi connector shells wherever possible.

There are several Delphi wiring booklets that I scanned in the manuals post.
1959 M35A2 LDT465-1D SOLD
1967 Dodge W200 B383, NP420/NP201 SOLD
1969 Dodge Polara 500 B383, A833 SOLD
1972 Ford F250 FE390, NP435/NP205 SOLD
1976 Chevy K20, 6.5L, NV4500/NP208 SOLD
1986 M1008 CUCV SOLD
2000 GMC C2500, TD6.5L, NV4500
2005 Chevy Silverado LS 2500HD 6.0L 4L80E/NP263
2009 Impala SS LS4 V8

RTFM... GM Parts Books, GM Schematics, GM service manuals, and GM training materials...Please include at least the year and model in your threads. It'll be easier to answer your questions.
And please let us know if and how your repairs were successful.
hatzie is offline   Reply With Quote


Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

All times are GMT -4. The time now is 02:51 AM.

Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2019, vBulletin Solutions Inc.
Copyright 1997-2013