*ALL NEW SQUAREBODY WIRING - To access the previous 10205 Harness manual, click here.*

This 27 circuit 1973-1987 GMC/Chevy Painless wiring harness was designed to fit the trucks, Blazers, and Suburbans*, whether C10, C20, or C30. It features a factory style bulkhead connector, allowing for easy mounting of the fuse block in the factory location, and has many of the factory connectors already installed on the harness out of the box. Including connectors for: the headlight switch, dimmer switch, wiper motor, ignition switch, blower motor & switch, blower resistor, and instrument cluster. Each wire is custom printed with the circuit identification as well as using GM color codes for easy installation.  Wire your Squarebody once and wire it right with Painless!

This harness does not support factory installed TBI fuel injection or computer controlled carburetors. 

* Doesn't support rear power glass, rear defrost, or rear A/C/Heat - many of these items are separate from the OE chassis harness. 

Factory Style bulkhead connector mounts directly in the original location - no modification to firewall is needed!

Most of the connectors come pre-terminated, making for a painless install!

High amperage charge wire is included allowing you to easily run modern alternators.  The included Midi fuse protects the system, getting rid of the troublesome fusible links that can leave you stranded with no easy fix!

Dual fuel tank ready!  If your Squarebody is a dual tank truck, simply use our included dual tank wiring harness to keep both fuel tanks functioning like the factory intended.

For the few non-preterminated connections, mastic heatshrink is included.  This will allow you to make professional and waterproof connections with a clean appearance!

Due to different front end configurations and bed lengths, this harness comes with open ended headlight and taillight wiring with extra length and can be paired with our light socket kits:

30350 - GM Pickup Socket Pigtail Kit (Single Round Headlights) (73-80)

30351 - GM Pickup Socket Pigtail Kit (Single Square Headlights) (80-87)

30352 - GM Pickup Socket Pigtail Kit (Dual Square Headlights) (80-87)

30353 - GM Suburban Socket Pigtail Kit (Dual Square Headlights) (88-91)