fuse box power supply wire..After reading another post (that i can not find anymore) about replacing the power supply wire to the fuse box with good results, i decided to do the same after i noticed mine was kinda old and crusty. turned out its a good thing i did because the stock wire is puny already and had broken, only to have the PO splice it back together with even smaller wire.

After the install i am amazed at the HUGE difference i noticed in my electrical operation and would call this a must do. the exterior and interior lights are noticeably brighter. the radio sounds much better and the truck even seams to run better (more power to ignition and sensors maybe).. and yes the horn is also much louder. also noticed less voltage drop when rolling up more then one window at a time.

I really wish i had taken pictures and will probably go back out and take it apart to take some tomorrow. I will try to give you a step by step without the pictures.

NOTE: I own and performed this on a 4WD 2nd gen 4runner with a 3vze and an automatic transmission and am not sure on the other generation pickups or 4runners. but should be very similar.


I used 4gauge wire with pre-connected hole tabs on each end of a 14 inch cable. that is all i had to buy, but you may have to buy a positive terminal connection with an extra bolt or one that uses a clamp to hold the battery cable to the terminal.

make sure the first thing you do is disconnect the battery, both positive and negative, and remove the battery to give you some extra room.

unbolt the fuse box by removing the 2 10mm bolts that hold it on the passenger fender.

then take off top cover and flip the box over and remove the bottom cover.

remove the main fuse from the fuse box, it is held in with a clip system similar to most connections. it will come out by lightly prying on the clip and pushing it out of the bottom of the fuse box.

follow the stock wire to the side it mounts to on the fuse, the stock wire is crimped to a plate that spans across two connections on the side of the main (80 amp) fuse, the crimp that holds the stock wire to the plate needs to be cut off at the bottom of the plate to do the mod with the same gauge wire i used. then use the factory bolt that holds on the other wire above the main supply clamp you just cut off to bolt on the new cable.

then run the new cable to a mounting place on the positive battery connector.

install the main fuse back into the fuse box, reversing the removal steps.

run the new cable through the stock location on the bottom fuse box cover and install bottom cover. (NOTE: the new cable was applying a small amount of pressure on the bottom cover causing it to bulge slightly, but should not cause the bottom cover to come off.)

bolt the fuse box back into place and re-install the battery making sure all connections are tight and clear of other connections.

if you have questions feel free to ask.. should take about 20-30 min for an average weekend wrencher.

Good luck!