The fusible link thread

The FL 1.25B fusible link is a common problem area on these vans. To start with it's in an odd place. It's tucked up in the body just in front of the battery box. To get to it you have to lay on the ground with a flashlight, reach up to lift, then yank down off it's holding post. Another odd thing (considering this location) is it's not in a waterproof box. It is protected, well, sort of, but certainly not waterproof. Note: This fusible link is only present on 86 - 89 vans.

Here is what it looks like while on it's mounting post.
http://i8.photobucket.com/albums/a23...v/IMG_0149.jpg

Here are some pix of what it looks like after being pulled down.
http://i8.photobucket.com/albums/a23...ibleLink-1.jpg

http://i8.photobucket.com/albums/a23...bleLink2-1.jpg

Considering it's over 20 years old, the one in the pictures above is in remarkably good shape. This is a west coast van though with fairly low miles (about 100k) so it's had an easy life. The protective box on this one was wrapped with electrical tape and it looks like somebody put some sort of white grease on the conductors too.

The "B" in the 1.25B relates to the diameter of the fuse wire. The bigger the wire, the more current it can handle before it blows. I don't have a conversion chart handy, but I'm estimating that 1.25B is equivalent to about 80A. You'd think by the mid 80's Toyota would have been labeling everything in amps &/or using conventional breakers / fuses. One would also think they would know better than to put a non-waterproof electrical connection (not to mention one of the most important ones) underneath a vehicle.......and oh yes, right behind a tire. Go figure :dizzy:.

Here is a replacement fusible link wire. It is still available through Toyota for about $15. It's Toyota part #90982-08276
http://i8.photobucket.com/albums/a23...al/part1-1.jpg


Here is the next most problematic fusible link. The FL 0.5G fusible link is the yellow connector going to the positive battery post inside your battery box. It is rated at 0.5G (based on wire gauge, I'm guessing about 20A). This protects the alternator sense circuit that links the battery positive to the "S" terminal of the voltage regulator (built into your alternator). If this link is bad or disconnected, the end result is solid "Christmas lights" on your instrument panel and a "full field" condition in your alternator. Full field is when the regulator tells the alternator to go to maximum output all the time and can be dangerous. A short trip probably wouldn't cause any problems, but long term use could cause multiple electrical problems (due to over voltage) and worse case scenario could end with a thermal runaway condition occurring with your battery. Thermal runaways are scary and dangerous. The result is usually a pile of molten lead, plastic and battery acid all over the place. Thermal runaways have also been known to start fires, so don't push your luck with a bad or failing FL 0.5G link. Here is a what a typical 20 something year old one looks like:
http://i8.photobucket.com/albums/a23...v/IMG_0158.jpg

Although slightly more protected than the main fusible link, this link is still in a harsh environment and after 20 years or so will probably need some attention. I haven't checked to see if these are still available through Toyota, but really didn't see the need for genuine Toyota here. If Toyota still has these, they will no doubt want more $$$ for them than what they are worth. I have found a good substitute for these through Summit Racing for $2.95. These PICO fuse holders are water tight and are rated at 30A. Since this is a "sense" circuit, there would normally not be any current here, so I am going to recommend using a 15A ATC fuse. Here are a couple of pictures:

http://i8.photobucket.com/albums/a23...v/IMG_0164.jpg


http://i8.photobucket.com/albums/a23...v/IMG_0155.jpg

These next fusible links are actually in a pretty good spot so they don't need much attention. Still, it's good to know where they are and what they do so I'm going to include these in this post.

These are located in the compartment behind the front passenger seat. To access, slide the seat all the way forward, peal the carpet back, remove the single screw that holds the access panel lid, and remove it. This fusible link box is right behind the power steering reservoir:



http://i8.photobucket.com/albums/a23...eFusebox-1.jpg

The EFI fusible link is rated at 30A and supplies power to the ECU and all the fuel injection related circuits. The AM2 fusible link is also rated at 30A and supplies power to the ignition related components such as the igniter, distributor, coil, and so on. The headlight fusible link is rated at 40A and you guessed it, it supplies power to the headlight circuit. The AM1 fusible link is rated at 60A and supplies power to all your accessories that come on when the ignition switch is in the "on" position. It is also the source of power for the starter solenoid circuit (trigger wire) when the key is turned to the "start" position. Important note: The AM1 fusible link does not just "pull-out" from the holder. There is a screw going into it from the side to hold it in place. Unless it's blown, it's best to leave this one alone.

Last but certainly not least is the FL 2.0L fusible link. This one could be considered the most important because it supplies power to ALL the other fusible links (except the yellow FL 0.5G) This one is usually not mentioned due to confusion about it's location and because it rarely fails. When it does fail, most mechanics will bypass it without even realizing it's there. This is because it looks like an ordinary wire coming off the positive battery post. The 1st 6" of that "wire" are actually the 2.0L fusible link. The other end of this fusible link hooks up to a white wire with a blue stripe and that's the same wire that feeds the Fusible link that everybody knows about (the FL 1.25B). Here is a picture of the FL 2.0L. It comes from the factory in a soft loose fitting gray plastic cover.
http://i8.photobucket.com/albums/a23...v/IMG_0168.jpg

Here's a picture taken from the wiring schematic that I marked up. Enjoy. Tim
http://i8.photobucket.com/albums/a23...v/IMG_0175.jpg

Thank you for this. I've not needed to work on the fusible link yet(that i can tell), but have read much on it and never seen a picture or found it when trying to find it(lazily and using written descriptions). Very helpful, and the 15amp fuse replacement is helpful too. -aaron.

Thank you for this amazing thread Tim!!! Here's a question, if there is enough cable and there is enough room,,, is there any reason the FL 1.25B can't be pulled up into the battery box area? I did this to mine so that all 3 FLs are inside, so I can access them in the same place,,, rather than getting 2 inside and one outside.

Being in CA I wouldn't think it would be worth the trouble to relocate. FWIW I've never actually blown that fusible link before so I never gave it much thought. Van owners in areas where they salt the roads have the most trouble with this particular FL & I could certainly understand those people wanting to relocate.

Just remember when fusible links blow they can produce an exciting shower of sparks. Batteries vent hydrogen, and they vent the most in instances of high current flow.........which also happens to be the most likely time to blow a FL:yikes:. I'm not saying you can't do it, I'm just saying these things are worth consideration and the location you choose may require a little more protection (just in case). Tim

Hi,

Just went to local Toyota dealer (southern Calif.) , I was informed that the fusible link is no longer available. Is that true? If no longer available what amperage fuse would one put in there?

Thanks,
Hiking

Depends on which fusible link you're talking about. Please specify.

Sorry for the omission of which fusible link:doh:da!
The one I'm refering to is FL 1.25B.

Hiking

I got one of these about 2 months ago, but I have a great Toyota parts guy. His attitude is order things even when they are shown to be unavailable. He's gotten me lots of things I thought were gone, but the parts supply on these vans is dwindling so I wouldn't be too surprised if they are history. FWIW, before I found my current parts guy I was told several parts were NLA. Since finding Brian at Tonkin Toyota in Portland, he's managed to get me several of these "unavailable parts" more than once. You might try another parts guy just to see if your guy is just being lazy. If this truly is NLA, then I'd look at other possibilities.

If the FL 1.25B box and the conductors inside are still okay, then I'd put some bulk FL link wire inside the box and save yourself the trouble of rewiring. The rule of thumb is the fusible link should be 4 wire sizes smaller than the wire it's protecting. I'm going to guess here and say the alternator wire is 8 ga, so if that's the case, you would want a 12 ga fusible link wire here. You can get FL wire at most auto parts stores in bulk for about a buck a foot. Here's some on Amazon.com: http://www.amazon.com/Pico-8124PT-Ga.../dp/B0002ZGBRE . Verify the size of the wire it's hooked up to, then select the FL wire based on that. Cut the length you need and crimp eyes on it to resemble the original. Be sure to use a high quality crimper like Klein and don't forget to use a dab of dielectric grease on the terminals to protect them.

If the FL link box is toast and you cannot easily find a replacement, then I'd probably use a big slow-blow fuse here. I'm thinking stock alternators are 65 amps, so a 70 - 80 amp fuse or breaker would be about right. You should check and verify wire gage, then size the fuse based on the maximum current the wire can hold. Here's a link to a wire gauge chart: http://www.powerstream.com/Wire_Size.htm .

I was able to order an FL1.25B from a Chicago Toyota dealer at a cost of $27.

While checking out the other fusible links, the ring terminal on the FL0.5G broke. I replaced the ring terminal, but tried to order a new FL0.5G green fusible link wire with plastic connector on one end and ring terminal on the other. The parts guy could not be sure which of 2 fusible links it was. I asked the prices of the 2. He quoted me $15 and $1. I ordered them both. What arrived were 30A and 40A plug in fusible links. Another parts guy at this dealership said the FL0.5G was part of the wiring harness and was no longer available.

At this web site, http://www.atlanticz.ca/zclub/techti...nks/index.html, I found a chart that lists fusible link wire sizes and colors and the amperage of the wires they are protecting. The colors and dimensions of these fusible links are the same as those on my Toyota. Although this site is about 1975 Nissan 280Z fusible links, I guess that the color coding in Japan is consistent across time and brand. So I am in the market for a 6" piece of Japanese 0.5 square millimeter green fusible link wire. I computed its equivalent to be AWG 26 gauge fusible link wire.

I have owned an 1988 van for 18 years, and I am just now finding out about the access hole behind the passenger seat--thanks to TOYOTAVANTECH.COM. Neither the owners manual or the service manual provide this information.

Today I was going over my battery and wires going to the FL 0.5G fusible link broke, the yellow connector going to the positive battery post inside my battery box. I immediatly disconnected the battery and wish to replace this piece. That said...How do I go about this?

Tim suggests purchasing a "Pico" electrical fuse holder. I purchased a waterproof 30A fuse from NAPA and will get the 15A ATC Fuse tomorrow. How do I install and repair this fusible link?

Do I need a new connector to the battery terminal or can I use the orginal if it looks good?
Do I strip back the wire, soder wire (new orange to OEM van wire) then heat shrink?


Any info will help. Thanks forum members!

How you fix will depend on how it broke and what condition the rest of the cable/terminal is in. If the damage is restricted to the yellow link, then cut it out and re-use the left over wire to splice-in the fuse holder. High quality butt connectors crimped on with a high quality crimper (like a Klein) would be adequate but solder and shrink tube would be better.

If the damage and corrosion extends beyond the small fusible link wires then you may need to replace the entire battery terminal. It all depends on the extent of the damage. Tim

My 0.5G fusible link broke at the ring terminal. I installed a new ring terminal onto the 1/8" shorter fusible link wire. I had to alter a ring terminal to fit. Although the length of the fusible link wire is important, I do not think that missing 1/8" will cause a problem. I tried to buy that fusible link from Toyota to have on hand as a spare. Toyota said that it wasn't available. Toyota also said that fusible link was part of the wiring harness which also wasn't available.

This fusible link was giving me problems before. If I hit the brakes, the stereo would turn off. If I flipped the fan onto full blast, the engine would choke out. I found it to be hanging by a single strand of wire. I spliced a piece of 18 gauge to it and that helped. Now I plan on deleting this fusible link altogether. Then I'm running 4 gauge from the alternator to the battery and it'll be protected with an 80 amp fuse. It's basically the leftover wire from when I had my stereo system before it was stolen. Then the wire that the fusible link was connected to will be tapped into that 80 amp fuse as well. Then I will be running more 4 gauge to under the dash to an aftermarket fuse box that will run my headlights, new stereo (if I decide to get one), and one of the fuses will be tapped in with a circuit that comes on when you turn the key to ACC (one click). I'm hoping this will fix all the electrical bugs once and for all and then my Van can stop eating expensive batteries.

Here's progress so far.

http://www.youtube.com/watch?v=Tzlj_P8fENk

"Out of the way cat, I'll crush your head in" :LOL2: :rol:

Did some more work today on it. Napa let me have the nuts and screws for nothing because it would cost them more to run my debit card. The mechanic who works there asked "you still have that thing?" Anyway, I mounted the new fuse box to the A/C amplifier. I ran the 4 gauge underneath. I just need to solder on a ring terminal and connect it to that nut where the alternator connects to. I'll have new video up in the next day or so.

http://i216.photobucket.com/albums/c...402_205107.jpg

And here's the video.

http://www.youtube.com/watch?v=FiNdqqzXZIo

Got a terminal soldered on the end of that wire now and got it connected. So far, everything is working great. Discovered the driver's side high beam burned out, so I replaced it. I turned everything on with the engine running and seems to be stable. I'm confident a wiring upgrade like this will get rid of some of the electrical gremlins in these Vans.
http://i216.photobucket.com/albums/c...412_144647.jpg

Went ahead and bought some 14 gauge fusible link from Napa. I assume this will be ok.

http://i216.photobucket.com/albums/c...420_175609.jpg

Then I went ahead and soldered it to the original female spade connector. Gotta love heatshrink tubing to make to look nice and clean.

http://i216.photobucket.com/albums/c...420_191936.jpg

Even though I wired the alternator directly to the battery, this fusible link still needs to be connected or the idiot lights will come on. I also found a constant 12 volt wire under the steering column where I can also spice some fresh wire to. I connected my multimeter to my new fusebox and that constant 12 volt wire in the steering column and set it to the milliamp setting and it looks like there's just a little bit of loss. The needle moves up just a little. If I turn on the hazards, the needle jumps up and down every time the lights blink. So, there's obviously some loss through the original wiring. So, I'm going to go ahead and connect that constant 12 volt wire to my new fusebox so the system can get some clean power and redundancy.

Hey Tim - Wondering what you would replace the 2.0L Fusible link with?

Been having christmas lights the past couple of days and just ripped out the battery and associated wiring and found the 2.0L AND the .5G have been "modified", essentially cut out and straight wire installed and not well done at that.
I have picked up a couple of weather tight ATO fuse holders and to deal with the problem.

I also have cut back the harness till I found the original white and white/blue wires.
Is 12G wire sufficient replacement for the white/blue wire??

I am clear that the .5G should be sufficient with a 15A fuse but not sure what to put in for the 2.0L??

For what it's worth, when I asked the local parts store if they had any fusible link wire, he said "yeah I's gots all kinds of fuses".
When I clarified my requirements, he appeared rather confused and told me there was no such thing.:cnfsd:
So a fuse it will have to be.
Thanks
BB