The Painless Performance 10101 harness is the most popular wiring upgrade for classic C10 trucks. Here’s a complete guide to the install.
What You Get
The Painless 10101 Classic Chassis Harness includes:
- 21-circuit complete chassis harness
- Fuse block with labeled positions
- All main harness branches pre-assembled
- Full instruction manual with wiring diagrams
Tools Required
- Wire stripper and crimper
- Heat gun and heat shrink
- Electrical tape (for final wrap only)
- Test light or multimeter
- Drill and grommets for firewall pass-through
Installation Overview
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Remove the old harness – Pull it completely and label what goes where on the firewall. Take photos before disconnecting.
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Clean and paint the firewall – Now is the time to clean, sand, and repaint the firewall. Much easier without wiring in the way.
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Route the new harness – Run the Painless harness following the stock routing paths. Use factory grommets where possible and add new ones for any new holes.
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Connect the fuse block – Mount the fuse block to the firewall in an accessible location. Connect the main power lead to the battery.
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Connect all circuits – The Painless manual walks through every circuit connection. Follow it exactly. Test each circuit as you go.
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Test everything before reassembly – Test all lights, gauges, accessories before closing up the dash.
Also upgrade to the Voltstorm HEI Distributor while you have the engine bay apart — removes the points maintenance forever.