FJ40 Wire Harness Reference - December 1978

[WaTrout88]

It looks like this guy was working with the same issue but never got an answer.
Ignition wiring help with a DUI distributor real time help!

Also, here is some good info from Performance Distributors. It sound like that 16-18ga wire that had previously been installed is supossed to be used for a tach meter not the main power source which needs to be 12ga.
http://performancedistributors.com/wp-content/uploads/2013/06/GMStreetStripD.U.I..pdf

 

[WaTrout88]

I emailed Performance Distributors. Here is what they said below. Why wouldn't this work?
>>>

No relay is needed. Just a 12 gauge wire from the starter solenoid to the distributor is all you need to power the DUI.

 

[FJ40Jim]

Because Toyota doesn't use a remote starter solenoid (like a ford).

 

[Coolerman]

Question is: what do they mean by "short amount of time" and what is the actual peak current? Might a properly rated slow blow fuse or circuit breaker work?

Yes a properly sized slow blow fuse could be used instead of a fusible link. I would think that the 25 amp surge mentioned on the Chevy forum is probably accurate and as for how long is a short duration? I would figure a second or two at the most.

Yes a relay would take the load off the key switch contacts. Keep in mind Toyota designed the OEM key switch contacts to handle the load a OEM ignition puts on them, NOT the DUI!

I would use at least an automotive rated (wide temp range and SEALED) 40 amp relay. Hella makes an excellent sealed relay and socket set. I can order you one if you want. Send me a PM about this.

 

[rghouse]

can someone PM me with this spreadsheet, google docs is requesting permission, thanks

Or just post a version in excel...

 

[StinkyPig]

And what does it mean when that pink wire is getting HOT?

 

[rugbyrules05]

Resurfacing an old thread on the topic of 1978 FJ40 wiring harness work.

I recently went through my main and rear wire harnesses for my May 1978 production FJ40. Using the OPs chart, several other posts, the pdf wire diagram and various other resources as a guide and updating based on my specific harness.

I sourced replacement connectors, wires, wire wrap, firewall grommets and various parts from Coolerman (aka Mark), CityRacer, and ToyotaMatt (understand folks may not have had the best experience with VintageTEQ, but i have done many transactions with him problem free, just know that sometimes he is slow on delivery). Added a relay kit for the HEI DUI distributor from Coolerman (thank you!) as the PO had not hooked it up correctly.

Below is a numbered listing of every connector starting at the passenger side horn through the harness to the drivers side horn. I added connector types, wire colors, wire guage and photos of the OEM connectors noting where they were not OEM to the chart. Unfortunately i did not get a photo of the completed harness re-wrapped and with replacement OEM connectors before installing back into my rig, so this will have to do for now.

Photos of chart below, see link to complete file in OneDrive for reference, note it is 78MBs so fairly large and can get slow when opening individual photo connectors.

https://1drv.ms/x/c/b8d9cb951da5b954/EUNijs3Ok39Km_btrPuem6IBwP_mSEQgTPBALiEnCeOWjQ?e=syjrIG

 

[woytovich]

Niiiiiiice!

 

[rugbyrules05]

Niiiiiiice!

Thanks woytovich, your thread was of tremendous value and inspiration to me when I started my harness rewire project! It allowed me to tackle what can be an overwhelming task for folks who don’t have lots of auto wiring knowledge with relative ease.

But I found once you unlock the magic of FJ40 wiring it is relatively simple and manageable to DIY.

What got me stumped initially was the splices in the rear harness where the wire color changes behind the tape!

So I took photos and noted where those splices occur and the color change for future wire explorers.

However, I did not take apart my main harness completely so have not noted where splices/color changes may occur there. If anyone has any additions or corrections let me know and I can update the file. Note the file is also editable so feel free to download or update on your own.

 

[nabbasi]

I found solid wires on my 78 rear harness and was very confused. I got it figured out after I found the splice near the transfer case.

I think I found a thread from mark (coolerman) where it was common that Toyota started switching over to solids before ‘79, but mine is an August build, which seemed early, but yours makes me think Toyota was purposely doing this.


I also went with a relay from mark for the distributor after ditching the igniter set up

I used parts from the same three vendors to get 90% of my working working (still don’t have interior room light or cigar lighter).

And will also say that I’ve had good experiences with Matt, including great conversations, but I wouldn’t consider his service timely.