High amperage fuses, more accurately called fusible links, come in several different forms. For many years American car manufacturers used a deceptively simple wire. It appeared to be ordinary electrical wire, but it was designed to burn in half in the event of a major short circuit. Very early on, foreign manufactured vehicles chose to use a more expensive approach--a self-contained, high-amperage fuse. It looks like an ordinary plug-in-pull-out fuse, but it's not, and that leads to confusion.
Remove the 80-amp fusible link located next to the battery. This 4-Runner circuit is designed to protect the charging components, including the alternator, regulator and battery. For example, the fuse will blow if jumper cables are incorrectly installed, inadvertently reversing the battery polarity. Pull the lower cover off of the fuse and locate two bolts. Loosen but do not remove the two bolts.
Pull the fuse up and out of the fuse holder. Two slotted prongs are built onto the fuse and designed to slide over the bolts that securely hold the fuse in place.
Install the new 80-amp fuse and guide it over the bolts. Tighten the bolts and make sure they are snug. Loosely fitted in place will cause arcing, excessive heating, melting of the insulators and lead to electrical failure.
