Locating them is tricky and requires careful inspection:
* Under the hood: Check the main harness leading from the battery, often near the starter solenoid or firewall. Look for any wires that are noticeably thinner than the others in the same bundle, especially those leading to high-current circuits like the starter motor, headlights, or ignition system. These are likely candidates.
* Inside the car: Inspect the wiring harness under the dash, especially near the fuse box. Again, look for thinner gauge sections within thicker bundles.
* Wiring Diagram: A wiring diagram specific to your 1968 Impala is *essential*. It will show the locations of the fusible links and the circuits they protect. A Chevrolet shop manual for that year is your best bet to find one. Online resources may also offer diagrams, but ensure they are accurate for your specific model.
How to tell if a fusible link needs replacing:
* Visual Inspection: Look for any signs of melting, burning, or discoloration on the fusible link. A broken fusible link will often show obvious damage.
* Continuity Test: The most reliable method. You'll need a multimeter. Disconnect the fusible link from both ends. Set your multimeter to check continuity (usually a symbol that looks like a diode). Touch the probes to each end of the link. If the multimeter indicates continuity (usually a beep or a low resistance reading), the link is good. If there's no continuity (open circuit), the link has blown and needs replacement.
Important Considerations:
* Replacing Fusible Links: Don't just replace the link with any wire. Use a fusible link of the *exact same rating* (amperage) as the original. Using an incorrect amperage can lead to further electrical problems or even a fire. The wiring diagram will specify the correct rating for each link.
* Safety First: Work on your car's electrical system only when the battery is disconnected to prevent shorts and injury.
* Underlying Problem: A blown fusible link is usually a symptom of a larger electrical problem (short circuit, overloaded circuit). Addressing the root cause is crucial. Simply replacing the link without fixing the short circuit will just result in another blown link.
Because of the difficulty in locating and identifying these components without the proper diagrams and tools, it's strongly recommended you consult a professional mechanic if you suspect a fusible link problem. Improperly dealing with them can cause more damage to your car's electrical system.
