yep, turned out to be way better then I thought. I have now realized that the better power supply lets my crap battery last longer during accessory use. so i can use my radio uninterrupted for about 45min before turning my truck on to charge my battery,,,

 

Well now that you know how to remove the fuse block and take it apart.

Perhaps it is time to replace the wire from the B terminal on the alternator up to the fuse block.

i use number 1 or 2 welding cable to replace all the grounds this has helped no end in charging and starting problems.

I also use marine battery terminals on all my Toyotas.

 

I just completed this mod, and I wish I would have done it the first week I owned the truck! So far, I can tell it has a little bit better throttle response, a slight increase in horsepower in the whole RPM range, and my horn sounds SO much better! Before it sounded like a sick duck, even with the truck running (alternator charging). Now, it blasts like a horn is supposed to, whether the truck is running or not. I still have yet to see any improvement in my lighting system, since it is the middle of the day and not a cloud in the sky.

Of course, both the supply wire and the body ground had been hacked by POs. The body ground had a butt connector and electrical tape splice. When I took the tape off, the wire literally fell out of the connector! At least the ground to the block was in solid shape.

I replaced both wires with 4 gauge wire that we had sitting around the house. One thing I would recommend, is to use a slightly longer bolt to attach the new supply wire with. Since the tab on my 4 gauge wire is so thick, there wasn't a lot of thread purchase left to hold that in place. An extra 3 mm would be about perfect I think.

I don't recall reading anything about this specifically, so the thing I want to add regarding this improvement, is the plate bolted on to the 80 amp fuse and crimped on to the power supply wire. When you snap the tab off of that plate, you realize that ALL of the current operating your entire electrical system (except starter motor), has to pass through this tiny amount of brass. That tab is maybe 1 mm thick, by about 4 mm wide. This is probably equivalant to about a 14 - 16 gauge wire! Regardless of how weak or small the supply wire is irrevelant due to the fact that this electrical 'bottleneck' exists.

After completing this, I would consider it an absolutely mandatory improvement. Especially considering how easy and affordable it is. Thank you everyone that has brought this to attention!

 

dude, just did mine on my '93 runner a couple weeks ago, replaced just the pos battery to fuse box link w/ 19" NEG cable from autozone (4g) and the windows go up and down faster! soldered it in at the fuse box and bolted on to the pos terminal. need to finish the rest but probably won't until I put a 3.4 in it, hahaha. This really works though...

search 'big 3 mod' or 'big 4 mod', depending on what you want to do

 

and yeah I lied about my 'big 3 mod', it's more like the big 2 mod right now; added a ground and that's it; need the alternator to battery link still....

 

Battery died on me yesterday. The first time it hasn't started since the battery was new except for the time the distributer cap went out. I found this thread and did the change. I should have checked the water in the battery! Every cell was low.

A 24" and a 36" cable did the positive and the ground. I used a piece of the old ground for the 9" body ground. I got 6ga from Oreillys. I was able to bend the end connectors enough to make them work without replacing any ends. Added one eye for the body ground. I left everything a shade longer so they wouldn't get fatigued from being pulled on.

I didn't find any bad corrosion but I don't live on the coast. The wire is spliced just like the wires above. It seems insane. It looks like the factory wrap on it to me.

I want a better battery terminal. I want the wires going into the clamp directly, not eyes halfway secured to a clamp meant for something else. I think the truck runs a lot better. Maybe that crazy idle when the brake is pushed in is gone? When I was fiddling with the old connections it started idling lower..........

It's such a stupid simple thing. I can't believe it could be so poor and make such a huge difference. I was actually going up a slight hill and accellerating in 4th.

 

My ground looked ok on inspection but I guess I'll redo that one too with 6ga and see if anything changes.

 

I replaced my power supply wire this evening. The old one was patched and spliced with smaller than original wire. I used a 6 ga battery cable I bought at Walmart for about $4. I just snipped the old wire off at the crimp on the brass plate beneath the main fuse. I trimmed the new cable to size and soldered on a connector and then used the bolt right above the old crimp to secure it. I can not tell any difference in performance, but now I know it is getting all the juice that it is supposed to plus looks better without all the splices and electrical tape.

 

try to remember, although your cables may look good, your only looking at the cover. you cant see the actually wire on the inside. that is where the corrosion and breakage happen..

 

I did this mod on my 4runner last night and now it will not start no cluck or anything from the starter or relay, must have knocked something loose in the fuse box. I also redid my alt cable and ran it from the Alternator to the battery with 2 gauge welding cable the same as my grounds and starter cable. So i have bypassed the 80A fuse for now but plan on installing a 120A slow blow fuse when I upgrade the alternator.

 

Uh, why?! No part of that sounds like a good idea.

 

2 gauge Welding wire was never going to fit in the stock fuse box. The only time I will have a problem is if the cable wears though and shorts on the body. That's not likely (fully protected in all rub areas) in the 2months till I get a high out put alternator and install the higher amp fuse. I'm not worried about it, how often has the 80A fuse blown on your truck?

 

I'm new to this forum and after a little searching around it seemed like this was the problem I was having. Went to my friends house today and sure enough with wire was all frayed and cracked. Followed this tutorial and I'm running as smooth as a top.

Thank you for posting this hyper informative step by step.

 

I think i need to to this. Thanks!

https://www.yotatech.com/forums/f116...roblem-271432/

 

I absolutely CANNOT get the main fuse block out. Toyota seams to have built a plastic clip that will hold the world on it's axis. Pried both ways, tried pushing from the top, pulling from the bottom, lubed it all up with silicone spray. Nothing. Any tips?

 

Are you talking about the 80amp (or larger) fuse? If so, you need to split the fuse box upper section from the lower box because that fuse has screws that hold it in there.

 

Yes.

 

I finally got the darn thing out. Here's my version of the fix. The cable I bought was too long with the rounded over end so I just ground it flat to fit. The screws weren't long enough to leave the two small red wires separated so I put those together and made the input just be just by itself. The shortest cable they had was 15", so it does quite a long loop down and back up to the battery, 9" or so would be better.

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You shouldn't just replace it with plain cable but with Fusible Link. FL is there to protect the wiring from overloads. Phibert has a write-up on FL replacement.

 

Isn't that what the 80A fuse is for?