1GR-FE Wiring Overhaul - A slow descent into madness

Quick links (first post in each project):
1. Big 3 upgrade - YOU ARE HERE
2. Headlight Services harness
3. Winch wiring/solenoid relocation
4. Control panel wiring, Warn EVO reverse engineering
5. Aux relay panel


Hello friends,

I've been prepping for a big wiring overhaul in my 1GR-FE equipped 2009, and finally got some small parts I've been waiting for. I'll be using this thread to document the progress of the project as I get through it.

This first post isn't HUGE, but it is a start. New terminals and rough-cut Big 3 wiring is done and ready to install and finish as soon as I get some warmer weather, hopefully in the next few days.

I've decided to use 1/0 for the starter and alternator runs, and 4AWG for the engine bay ground, factory underhood fuse/relay panel feed, and aux fuse panel feed:



The ordnance terminals, wire, adhesive lined shrink tubing, and some of the lugs seen here were purchased from AC/DC Wire and Supply. I have no stake in sending your business to them - they are my preferred small quantity wiring supplier and I believe in shouting out businesses that I like to deal with.

The solder pellets and 4AWG lugs were purchased from other vendors.

I decided to do everything the best way I know how, which in this case is soldered and crimped for that belt-and-suspenders peace of mind. Additionally, high temp adhesive lined shrink tubing is a must for helping keep corrosion under control long term.




It was a TIGHT squeeze to get 2x 1/0 and 1x 4AWG through these "military style" boots, but it did fit.



Next up will be a dry install to determine final length, terminating, and installing before moving on to the headlight harness upgrade.

 

I’ve ordered from AC/DC on eBay quite a few times. Great for quality terminals and such rather than Amazon mystery pot metal.

 

Can you post up the lengths of wire you used? I have been wanting to do this with my truck for a while now and want to make sure I get enough (or not too much). While I have the 4 cyl, I assume the lengths will be similar enough.

 

Removal of old wiring and dry fitting the new stuff today.

This is how we started the project, fender ground bolt sheared on removal:


Not to worry. There are a couple of other threaded holes on the same side, closer to the firewall, and I have some factory bolts from something (I don't recall what) in the interior that fit. We'll get to that later.

I was going to try to disassemble the wiring harness in-place and not touch the things I wasn't replacing, but I ran into a heck of an issue trying to get the plastic housing/loom/wire guide apart from where it hangs on a bracket from the alternator. Every guide I read and video I watched glossed over how that thing comes apart.

After messing with it for a while, I proceeded to remove the entirety of the harness, brackets and all, that contains the factory runs for the alternator and starter:


Of course, once I had it out and in my hands, it was obvious how it came apart:


If you are curious, I posted some more detailed photos HERE of how that housing/loom/guide looks up close, so maybe you can have a better time of trying to take it apart in-place.

At this point, the truck is unable to go get its own parts - the critical point of any project that involves killing your truck in order to make it better:


I wirebrushed the wiring harness brackets and put a beer's worth (3 coats) of black rattlecan on them, since I'll be re-using them:


With the brackets dry enough to touch, I put the brackets back in place and then loosely zipped the positive wiring in, so I could massage the wire routing for dry fitting and trimming:


Here's a shot of the alternator placement. This, and cutting the starter positive lead, is as far as I got today before deciding to go find something else to do:

 

Subbed. I too want to know how long to cut these cables for the big three. I will enjoy watching your progress!

 

Planning on doing the big 3 for my audio system soon. Keep posting updates!

 

Edit - If you're following this to see about doing it yourself, be sure to check out THIS POST farther down in the thread for the correct installation of the alternator->fuse box->battery runs.

Put the lugs on everything that had already been fitted last night and got back to it this morning. Dry-fit the last two connections and put them in, and then did a final check for fit and connections.

Here you can see how I'm re-using the factory bracket. This photo shows BEFORE tightening up those zip ties, which are temporary anyway:


Previous owner went after the positive terminals with an angle grinder or something at one point, and left me with this partial ring terminal on the factory wiring coming from under the fuse panel:


That wire was quite corroded, so I wire brushed as much as I could of the crud off after cutting back for a new lug. I'm not happy about it and when I get back into this wiring to tidy everything up and heat-wrap/loom certain areas, I'm going to pull the fuse box and replace this wire as well.

Either way, I got everything in place in the fuse box:


Edit - The above configuration "works" but cuts out the high amp alternator fuse. Don't run your truck this way. The correct wiring path is shown in THIS POST.

And everything put back where it belongs:



I have some wire loom, heat shield, and related stuff on order. I did manage to get a new headlight harness put in as well after verifying that the truck is back in a running condition. I'll document that better when I get back into everything to run the wiring permanently.

Don't worry, when I do THAT, I'll be sure to get measurements for everyone who can't be bothered to get under their own hood. (-;

 

The yellow arrow wire is coming from the battery. But where is the red arrow wire coming from? aftermarket accessories?



I’m trying to figure out what to do with the bottom of the fuse box wire discussed on another thread.

Nice write up btw.

 

Excellent writeup, and thank you for sharing the pics of that cable bundle.

What's the investment? About an hour of cable building, and two of remove/install? It looks like a 5-6 beer project overall.

ETA: 4-5 if you're working quickly.

 

Thanks. The red arrow IS the bottom of the fuse box wire. I'm not actually sure where it goes, but I'm going to find out when I go to replace it - that's the one I mentioned being corroded badly. I had to put a new lug on it because mine was all jacked up from PO doing God knows what to it, and without being sure of where it goes (I'm GUESSING it's the positive rail for the fuse box) I wanted to make sure it was still in the circuit in a known working configuration.

Edit - The above configuration "works" but cuts out the high amp alternator fuse. Don't run your truck this way. The correct wiring path is shown in THIS POST.

Thanks for the kind words.

I think your numbers on labor hours are about right if you're already practiced at cable making and familiar with the details of the wiring, and decide to go directly for the full removal as opposed to monkeying around with that wire guide in place for too long. I could probably do this a second time in three or four hours total, but I took this very slow to avoid costly mistakes. It's functional the way it is, but once I get delivery of some heat resistant loom and a particular oddball part to test an idea, it might end up being really nice for a very small additional parts cost and a very small additional labor cost.

 

If you look back to where I left off last time, you'll recall that the wiring is all run, and kind of loosely zip-tied together just to keep it from rattling around or rubbing on anything while I drove around for a few days waiting on loom.

When the loom and stud boots came in, I cut all the temporary mounting zip ties, pulled the thing out, took measurements, and installed boots:


Note: This photo and one or two others show "Alternator +" going directly to the battery terminal. Do not run your truck this way. The alternator should run to the threaded post inside the fusebox (Called "2E" in Toyota reference material) as pictured earlier in this thread. The lengths shown in my posts are correct. For a full explanation of the error in this photo, check out THIS POST.

Detail shot of the boots:


Then, I put it all back in and re-installed the fasteners LOOSELY, to allow some flex while routing but also keep them in place so I could pull things snug.

THIS IS KEY! Start your routing from underneath and go upwards, imagining that these wires will all be inside of a loom together. I put a ziptie everywhere a cable separated out from the bundle:


Go slowly and patiently, and once you get to the top front bracket (the one attached to the wheel well, under the battery), remove the fasteners and pull the whole bundle out again. Sigh. It will look something like this:


I installed the starter end of the loom like so:


Then carefully feed it back in, with the loom loose around the rest, and install from the bottom. Again.

I don't have pictures of the next part because it was extremely fiddly. From here, you need to route your starter and alternator sensor wires through the loom while the bundle is in place. Then, once they're connected, ziptie your loom closed the same way you saw in the pic of the starter end above - a ziptie before and after every cable that exits.

If you use the aluminized heat shielding loom like I did, it's quite malleable and if you're slow and patient, you can do quite a clean job of molding it before attaching zipties.

Here's a couple angles of the finished product.

The starter from the bottom of the driver front wheel well:


Alternator through the driver front splashguard:


Alternator from above the fusebox, where you won't be able to fit your actual head:


Top view, standing in front of the driver's side headlight and looking down:


If I ever take this stuff out again (and I will eventually, either to clean up rust in the engine bay or replace the intermediate steering shaft or the alt or the....), I'll finish the loom job with some self-sealing tape over all the gaps where the exit points are. For now though, honestly, I think it's just fine.

 

I saw another guy ground from the battery negative terminal to the frame by mounting here.


That replaces the ground cable you had there from the block.



credit: http://www.bodenzord.com/archives/477

 

There is a factory ground there, but it's not actually necessary with the larger gauge replacement wire (the ground path from starter to battery is going from ~4 AWG to 1/0 AWG with this modification). It's certainly possible to run another short chunk from the starter ground to there (which I have read referred to as the "shock tower ground") with little effort other than a couple more lugs to solder and crimp.

If you're referring to grounding to the body/frame instead of the busted off one next to the battery, I ended up using one of the other unused threaded holes closer to the firewall up above - I meant to snap a pic of that earlier and post an explanation of it.

If you're referring to establishing a ground path directly to the frame, that's already done via the starter through the block and mounts.

 

Subd'

 

I'm on the same boat with my rewiring project (doing it while I have the truck down for other reasons). I am figuring that placing a ANL breaker between the battery and the alternator would help avoid the overriding of the stock alternator 140A fuse. I think that's a flaw found on the design of the former member here that used to make similar wires (bamatoys). Did you get any codes or errors when you tried running it this way? Curious to see your solution.

 

No codes or errors, and honestly could probably run the truck this way with no serious problems as long as one does not add too much additional electrical overhead to the system.

What I'm actually going to end up doing in the shorter term is replacing the "under the fusebox wire", aka 2C, with a higher gauge wire and running it back to the battery; and then running the alternator wire back to the stock location, 2E (the threaded stud inside the fusebox). This will put the alternator back behind the high amp fuse where it really belongs.



(Edit: Shame on me for not properly crediting @caribe makaira for his help and patience, the above diagram came from him as did invaluable guidance)

2C appears to be held in place inside the guts of the fusebox by a bolt threaded into a common bar. I have a used fusebox on the way so I can chop stuff up if I end up wanting/needing to, and if I don't, I'm considering using that second factory fusebox mounted on the passenger side as my aux fusebox/dist. panel rather than building a Bussman.



Bend a standard 1/0 AWG lug to 90 degrees in a vice and then open the far end of the hole just a bit with a round file and you can feed a 1/0 alternator wire to 2E.

 

To gut the fusebox, start by taking your battery out. Take the cover off the fusebox, and get the fusebox gutted.

There are several clips that hold the fusebox assembly together:


Start with the front and lift gently by the wire that feeds the battery (the "2C" wire, labeled "Fusebox +" in my photos above), then work your way backwards (as oriented in the above photo).

Once you get the fusebox lifted (it won't come all the way out without a lot more work, and it's not necessary to do so), wedge something like so to keep it in place while you work:


The bolt holding in the factory wire has a 10mm head. Take it off and remove the factory wire. Be sure to drop the bolt way down in the guts of your engine bay.

Notice the small alignment tabs in the factory location. Gently bend them down so your new lug will sit flush against the bus plate:


Insert your new wire the same way you took the old one out. 4AWG fits perfectly where the factory wire used to run. If you used a 3/8" terminal, you'll need a washer for that 10mm bolt. I think a 5/16" terminal here would be better, but I didn't have any.

Button it back up, and congratulate yourself for not breaking anything and only dropping that little bolt 3 times:

 

coming from the other thread. Have you noticed any differences in your electrical system? Starts faster, lights brighter etc?

 

Does “aluminized” mean you used CCA(copper clad aluminum)? It’s less costly and less weight than pure copper wire but doesn’t have the same current capacity for the same size.

 

It does indeed start a little faster.

No, the wire loom is aluminized, not the wire. The wording is a little ambiguous above, I edited it for clarity.