Where is the fusible link for alternator charging system on a 1990 mercury cougar?

There isn't a single, easily identifiable "fusible link" in the traditional sense for the alternator charging system on a 1990 Mercury Cougar (or most modern cars). The protection for the alternator charging circuit is usually integrated into the wiring harness itself or within a larger fuse block. It's designed to be a heavier gauge wire that melts under excessive current rather than a separate, easily replaceable link.

To find the protection for your alternator charging circuit, you should:

1. Check the Under-Hood Fuse Box: This is the most likely location. Look for fuses or circuit breakers of a higher amperage (30 amps or more) that are labeled "alternator," "charging," or something similar. There might also be a large fuse or a fusible link incorporated *within* the fuse box itself – it might look like a thicker wire with a slightly different color or texture than the rest.

2. Check the Battery's Positive Cable: Follow the positive (+) cable from the battery. Sometimes, a fusible link or section of heavier-gauge wire is incorporated *within* this cable, near the battery terminal or where the cable connects to a larger harness. This is less common on a 1990 model, but possible.

3. Consult a Wiring Diagram: A wiring diagram specific to your 1990 Mercury Cougar is the best way to definitively locate the circuit protection. You can find these online (sometimes for a fee) through sites specializing in automotive repair information, or you might find one in a repair manual for your vehicle.

Important Note: Working with automotive electrical systems can be dangerous. Always disconnect the negative (-) battery terminal before starting any work. If you're not comfortable working with car electrical systems, it's best to take your vehicle to a qualified mechanic.