76 K5 Blazer

[76BLAZER30]

I am getting ready to install a pinless wiring harness for my 76 Blazer....any tips or suggestions.

[68Timber]

Welcome to 67-72! I've never rewired a truck. Hatzie knows a thing or two about wiring these trucks, maybe he'll see this and chime in.

[hatzie]

First rule... Be patient and check everything twice.
I usually lay things out on the garage floor and bundle wires together in groups that are terminating in the same general area.

I'm not a fan of the hardware store nylon covered crimp on connectors. They're generally too light for the task and they look cheap.

When you properly crimp a terminal the wire is actually pressure welded to the terminal. If you cut through a properly installed terminal and sand the cutoff end you will not see many if any gaps between the individual wire strands or between the wire and the terminal. This type of bonding can't be done without the right tools. Crimps done this way will last a long long time.


You'll need a few tools.
Xcelite 101S wide range Adjustable Strippers or Xcelite 105SCGV stripper cutters.
Xcelite SK2S5 Dikes... believe it or not these are $13 at Home Depot as a set with some oddly shaped but very handy, for electrical terminals, needle nose pliers. These are for fine work not 5 wires at a time. They cut wire ties off close enough to the latch that the sharp ends don't slice up your hands.

Terminal Crimpers
12085270 Ratcheting Four cavity Delphi Metripack & Weatherpack
12085271 Ratcheting Five cavity wide range for Delphi Packard 56 & 59 along with a host of other F-Crimp terminals.

These two tools crimp terminals in two operations. First the wire then the insulation so they are not single terminal family specific like the one step tools. They will properly crimp every terminal you're likely to encounter on a 1976 GM Light Truck. They are pricey (between $89 & $105 each) but you're doing an entire harness not just a handful of terminals.

Terminal extraction tools
SIR Tools 9024 & 9025. They can run between $25 and $45 each. They are worth every penny. These are the Swiss Army Knife of terminal extractors. They fold up nice and neat like folding Allen keys so they don't get broken in the toolbox. 9025 is the one to get for a fairly wide range of terminals. 9024 will extract ECM terminals along with Metripack and Molex sensor terminals. I have used the Lisle Hexagons but they are unwieldy... with the tools you aren't using poking your hand. You can break and bend several tips if you drop them too.

1/8" wide wire ties. Not the 1/4" wide ones.

Don't pitch the original harness sections. Many of the connectors can be re-used with new terminals on the Painless harness including the firewall bulkhead plug, headlight, wiper motor, Instrument Cluster, and ignition switch. Mark each connection with masking tape and a sharpie. It'll give you an idea of how far the connector is from the fuse panel or bulkhead plug.

The 1976 wiring diagrams have all of the connector part #s. With the connector part # you can generally find the correct terminals with a minimal amount of detective work. Delphi has datasheets for a lot of their obsolete connectors listed online.

GM mostly used Packard 56, Packard 59, and Pak Con connectors on the 76 chassis.
If you find you're having difficulty sourcing some terminals from the usual suspects like Waytek Wire and Del City to name a few... Gmachinz (Harnessworx) fabricates new sub harnesses. Drop him a line and see if he can sell you the piece you need.

The taillight sub harness has over-molded Packard 56 connectors on the 1973-1983 chassis. You can buy and install the 2x2 4 terminal Weatherpack connectors that GM used on the 1984-91 chassis with no issues.

Some of the Sub-harnesses like the heater or heater/AC harness and taillights are usually not included as a Sub Harness.

The Alternator 12ga charge wire and the battery cables are some other pieces that will need to be scavenged from the old wiring or fabbed from new parts.