BJ74 Fusible Link -Intake Manifold Heater

[Glenn-BJ74]

I discovered my fusible link for the 13BT intake manifold heater (i.e. like glow plugs) is blown. I contacted Toyota to see is they have a replacement fusible link for the BJ70 (CDN spec), but they said that part is obsolete - not longer available.
The cross section of the melted wire is roughly 0.07" (near as I can tell as it was distorted), so I replaced it with 16 gauge AWG (0.066").

Is the wire in a fusible link designed to melt as lower amperage that ordinary wire at the same cross section and if so, should I be using smaller gauge wire?

Anyone know what those heaters draw in amps at 24 volts ?

Thanks for any info.

 

[kbushnz]

Hi Yah

Fusible links are just normal gauged wire which will melt if overloaded. And are sized to protect the wire loom.
There are some rules of thumb and several website which discuss in detail.
The biggest issue is once you have made one, protect it with the right insulation. As you dont want a live wire exposed. Or heat melting into other wires / components.

Here are a few links to read... I am sure Google will help.

AeroElectric Connection - Fusible Link Fabrication

http://www.oldspower.com/vb/attachment.php?attachmentid=18414&d=1249279938

You could also head to the breakers yard and find some from another vehicle.

 

[Radd Cruisers]

Glenn;

You can buy fusible link material at Napa and others. The FSM lists the cross-sectional area in mm^2 that you should have for the application. The requirement is listed next to the fusible link symbol.

The glow screens draw a lot of current - haven't measured it, but it's a lot. A four glow plug system in a 12V diesel will spike to 80 - 90A and quickly settle in to about 10A Per glow plug (depending on the system) and then dropping off as they heat up.

My feeling is that the glow screen, which has two stages, will easily draw 25 - 30A (once it settles in) at 24V, but I haven't tested it. The spike on initial application will kill a fuse, but not a fusible link.

~John

 

[Glenn-BJ74]

So the manual says 2.0 sq mm fusible link

Thanks -- that helps. I saw that in the FSM but I could not tell what the units are.
So if the area is 2.0 mm^2, then solving for diameter = 1.596 mm, which converted to imperial units is 0.063", which corresponds to a 14 gauge AWG (see below), which is heavier than the 16 gauge I used.
I used over sized insulation (with an air space) so if it burns up it will be still contained and insulated. If that happens I will go to 14 gauge. Very interesting.

American wire gauge - Wikipedia, the free encyclopedia

 

[Radd Cruisers]

I'll see if I have time to measure the draw today for you.

The insulation that comes with fusible link wire is less prone to burning up and smoking like the plastic insulation that comes on normal automotive wiring.

~John

 

[fireball]

Wiring on my fusible link was brittle and broke during a recent trip to UT, so I need to order a new one. Does anyone stateside have one? There's a few shady looking eBay options but wanted to check first to see if someone had it more readily available.

Thank you!

 

[jblueridge]

I make my own with generic materials.
I used 14 gauge fusible link wire for that one.

 

[Felde]

Make sure to use dedicated fusible link material. As a fellow said above: Fusible link material has a special insulation that stands even once the core (as intended) melts.
As far as I know, the material goes by color-code and length to get the resistance right. I have no idea, though, whether the color codes are international standard.

 

[ToyotaMatt]

i hand make any VINTAGE Toyota fusible links to order , as long as i have the correct electrical connectors


i ONLY use JAPAN fusible links wires per the EWD and FSM spec's

 

[fireball]

Awesome Matt, thank you for chiming in! I just sent you a message request through your website.

 

[jblueridge]

If there is an international set of color codes they are ignored in the USA.

 

[fireball]

@ToyotaMatt Is the CONTACT FORM on your website the best way to get ahold of you? I'd like to order two fusible links for my truck please.

Thank you!

Ben / Fireball

 

[ToyotaMatt]

@ToyotaMatt Is the CONTACT FORM on your website the best way to get ahold of you? I'd like to order two fusible links for my truck please.

Thank you!

Ben / Fireball

please PM me here on MUD

best way

we can go over your particulars in a technical format , fsm approach


i need photos and LOTS of them too of your exact needs and set up please


fusible links vary wildly from years to years and models to models too


i ONLY use real color coated and numbered spec;'s visible FUSABLE LINK wire LEED material period

i don't cut corners here , because i have no reason to , if i can't source the needed connectors ?

then we have other options too ,


nothing is impossible if you simply do it correctly ..........


everything IS possible if you use OEM japan parts


nothing more

nothing less




matt

 

[fireball]

Hi @ToyotaMatt I am sending you a PM but also posting these photos here. Pics of the fusible link on my JDM 24v bj74:

 

[ToyotaMatt]

Hi @ToyotaMatt I am sending you a PM but also posting these photos here. Pics of the fusible link on my JDM 24v bj74:

View attachment 3027570

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awesome TECH details and photos here ...



this KUSTOM BJ74 fusible links you need made up here is pretty straight forward for me , i DO have all the required OEM and JID JDM Electrical Parts and Supplies here

at the SKUNK-WORKS LAB ,


with only one un-known exception , the LINKS Side 3 PIN Female Connector Housing ? do we or anyone here on MUD in DIESEL TECH. have any confirmed example

PICS. ?


the profile and key-way KERFS are well .........very specific ?



i will have to dig a bit on this , but i have many dozens of this similar shape housing we need , ill report back here with TECH Pics , of what i come up with ....

 

[jblueridge]

That’s the same setup as originally on mine. The 2 pin connector uses the 0.312 brass disconnects. I never did find the same connector housing which I think is fire resistant, maybe Bakelite.

 

[ToyotaMatt]

Hi @ToyotaMatt I am sending you a PM but also posting these photos here. Pics of the fusible link on my JDM 24v bj74:

View attachment 3027570

View attachment 3027571

View attachment 3027572

View attachment 3027573

That’s the same setup as originally on mine. The 2 pin connector uses the 0.312 brass disconnects. I never did find the same connector housing which I think is fire resistant, maybe Bakelite.

it's not a bake-lite composite , simply 30 year old UV rated / Chemical resistent NYLON that expired its life cycle now , got brittle and snapped from age and time related stress fatigue


there is a reason TOYOTA did not continue to use the UN-Sealed ones from the 1980's and transiioend to the sealed water proof and better composites modern materials
shown below ,

NOTE : Colors of the below connectors housings are a non-topic as far as TECH really goes , as long as there NOT natural or white color they are a improved design ....


that LINKS / device side 2 pin female connector housing is indeed one after seeing the tech pics above is simply a non obtainable NLA / Disc. service part from long ago ., i have tried to source them and they no longer exist ...



so on to plan B witch is NOW Plan A ...........


a better modern 2 PIN water proof and chemical proof mating connector set up that will require NO chopping of wires o your harness side to be clear , you will de-pin

the 2 large gauge brass MALE terminals with a very special PICK tool for exactly this purpose ,

extract them and simply plug and play them into the new HARNESS side MALE housings i provide , consider it a update or upgrade same in kind



only thing u MUST be keening aware of is to keep the POLARITY the same on both my connectors ill explain more on that later ...



here is some pics tech so u better understand my above 411 :

 

[ToyotaMatt]

That’s the same setup as originally on mine. The 2 pin connector uses the 0.312 brass disconnects. I never did find the same connector housing which I think is fire resistant, maybe Bakelite.

Hi @ToyotaMatt I am sending you a PM but also posting these photos here. Pics of the fusible link on my JDM 24v bj74:

View attachment 3027570

View attachment 3027571

View attachment 3027572

View attachment 3027573

These are the large correct gauge terminals size specs as as @jblueridge correctly mentions above ,

Note the modern features

We will keep the 2 blacks together

And have a black and green

And of course the ring terminal link going to the single stud lug little black junction box too

I’ll fabricate the actual fusible links here and report back with tech pics

If you are unclear about a particular detail it will make sence after u see my assembled end product made to OEM specs …

The round housings also come with a rear end rubber seal plug too

So water and battery acid chemical resistant and state of the art modern as possible is the way forward here

 

[ToyotaMatt]

Ok presto :

well ……

as best to presto as we can in 2022 ….

BJ74 Fusable links update plug and play kit

Below are some step by step pics in chronological order

I tried to simply set the end user / land cruiser owner operators up for sucsess , even pondering what if the planned de-pinning of the current harness side old 2 pin connector housing went south for say a corroded brass male terminal spring tang and made it useless ?

So I include both harness side new needed male
Matching different color housings and more importantly a set of correct guage harness side wire solid brass terminals just in case ?

Or

Maybe replacing a 30+ year old crusty crimped Plant A-11 terminal is simply better then not ?

The jury will find out soon enough so …

Success set up plug and play is simply our way …


After final assy. I hyper inject fully synthetic Di-Electric Grease into all 4 female housings to pre-lube up the final mate on the BJ or any other land cruiser for that matter as this was common practice by toyota on day 1 and also the creamy white low tech crap some of you may have seen or had to deal with on a recent or past purchase of a toyota fusable link that. Is still a good current part # for the 80 series I can think of right now today comes pre - lubed

So if it’s tue TOYoTA way it’s my way too , Except I’ll out FOX them as I like to so and upgrade to a % pure fully synthetic food service and marine grade far far superior at all levels

More on that later …

 

[ToyotaMatt]

Here are the included OEM japan spec. YAZAKI Rubber terminal safety boots ...

They son of a guns are absolutely the best battery terminals B+ protection. covers mankind have crafted to date.


Flexible , a tad soft to the touch , yet tough as a WWII German Tiger Tank !

And well still thankfully still made in Japan.

I will go on the record and say these are. Life time service part in every way I know that one can be …

Note : the carefully thought out cavity that both hugs snuggly and protects the 12mm hex nut like nothing else could

It’s keep the cover centered and in place sturdy too ...

I discovered these on my 1998 T-100 i bought new off the lot. And only parted with a few years ago and that dam cover outlasted anything else under the hood ..