Use a verified electrical layout with clearly marked circuit ratings before touching any wiring–this prevents damage to harnesses, switches, and onboard devices. Models from the late seventies typically rely on a simple panel located under the dash on the driver’s side, where each protective element corresponds to lighting, ignition, wipers, heater motor, and auxiliary circuits. Ratings usually range between 10A and 30A, with higher values reserved for blower and headlamp feeds.
The panel layout is arranged in rows, often with labeling stamped directly into the plastic housing or printed on a metal backing plate. Pay attention to the color coding of wires: orange commonly indicates constant power, pink or red connects to ignition-switched lines, and black serves as ground. Misplacing even one protective insert can interrupt multiple systems, especially where shared feeds are used for gauges and interior illumination.
Corrosion and loose contacts are frequent in vehicles of this era. Inspect each terminal for oxidation and ensure tight seating. If circuits fail intermittently, check not only the protective elements but also bulkhead connectors and ground straps. Replacing old glass-style inserts with identical rated parts maintains original circuit balance and prevents overheating.
For accurate restoration or troubleshooting, match the layout to the exact trim level and engine configuration, as optional equipment like air conditioning or towing packages alters circuit allocation. Keep a printed electrical layout in the glove compartment for quick reference during roadside diagnostics.
1979 Chevy Pickup Fuse Box Diagram: Practical Guide
Locate the panel under the dashboard on the driver’s side and verify each circuit using a test light before replacing any element; match amperage strictly (typically 10A, 20A, 25A slots) and inspect for corrosion on terminals. For lighting faults, check the labeled positions tied to headlamps and tail lamps first; for ignition issues, inspect the slot linked to the starter and ignition switch. Clean contacts with electrical cleaner and a small brush, then reseat components firmly to avoid intermittent loss of power.
Use the original wiring chart to trace circuits and prevent misplacement. Follow this checklist for faster troubleshooting:
- Turn the key to ACC and verify accessory circuits (radio, wipers) with a multimeter.
- Switch to ON and confirm voltage at ignition-related slots.
- Check continuity across each protective element removed from the panel.
- Inspect harness connectors behind the panel for loose pins or heat damage.
- Replace any blown component with the same rating; never upsize.
- After replacement, test each circuit separately to isolate remaining faults.
For recurring failures, trace the wire path to locate shorts against the chassis, especially near steering column brackets and firewall pass-through points. Secure loose wiring with clips and add protective loom where insulation shows wear.
How to Locate and Access the Fuse Box in a 1979 Chevy Pickup Step by Step
Check the driver-side lower dash panel first: the electrical panel is mounted beneath the steering column, slightly to the left, secured by two visible screws or clips. Use a short Phillips screwdriver to remove the fasteners, then pull the cover straight toward you without twisting to avoid cracking the plastic.
Once the cover is off, identify the rectangular panel with multiple colored blade links arranged in rows. Keep a flashlight handy, as lighting under the dash is usually poor. The mounting bracket may sit at a slight angle, so adjust your viewing position rather than forcing the panel.
Access from the Engine Bay
Some versions also include a secondary electrical block under the hood near the firewall on the driver side. Release the metal clips holding the protective cap and lift it upward. Dirt and grease buildup are common here, so wipe the surface before opening to prevent contamination inside the contacts.
Disconnect the battery’s negative terminal before touching any connectors. This prevents accidental short circuits while handling the panel. Use a 10mm wrench, loosen the clamp, and move the cable aside so it cannot spring back.
Handling and Inspection Tips
Pull each link straight out using needle-nose pliers if fingers cannot grip it securely. Inspect for broken metal strips or dark discoloration. Reinsert components firmly into their slots, ensuring full contact. If resistance feels uneven, check alignment instead of applying force, as the plastic holder can crack under pressure.