Replacing the alternator harness

The eBay connector came with short leads installed, but I pulled them out and slipped in the spade connectors already on the alternator harness wires:
Attachment 1655

The connectors on the short leads each had a tang that clipped them into the shell, but the ones on the harness did not, so to keep them from backing out when the plug was inserted, I potted them in with RTV:
Attachment 1656

When the harness is installed, at idle the battery is charging and the Christmas lights are still gone:
Attachment 1657

Hi! I have been looking up how to connect the alternator to the harness for days now. I just replaced the alternator in my van and when we were disconnecting the old one realized that the plug was missing. What I have instead is the wire in the uploaded photo, which is obviously connected to the wiring harness but is definitely not long enough to reach the alternator. It's pretty clean and the area around the terminals on my old alternator is pretty clean so I can tell there was something connecting the two parts. I looked all over to find what could have been connecting that part to the alternator, and ended up ordering this:
http://www.ebay.com/itm/NEW-NIPPONDE...5d6436&vxp=mtr

So, this connects to the alternator but I have no idea what to do with the three wires. I have seen some instructions on which wires go where, but how do I connect them with that weird harness plug that is already in my van?

https://www.toyotavantech.com/forum/...ll=1#post10734
Timsrv, Post 28. That's which color wires go to it.
As for electrical connectors-I would get one from the junk yard and solder/heat shrink a used one on. Or if you can't find that male harness for that connector you could use three sets of spade connectors and make your own "harness".

This thread seemed like the best place to post this. I'd like to fab together a new alternator harness. I don't know jack about wiring/electricity etc., but I watched a ton of McGyver episodes growing up so I bet I could figure it out with a little help. ha! Thanks..

Here's what mine looked like as I just took it out and stripped the decaying flaking wrapper to old harness.
Attachment 1734
alternator connection on left. "+ box" on right. I did not unwrap and remove oil level sensor wire usually bundled with the harness. It looked fine and is working.

I'm stuck at what kind and size/gage wires to get??? I may save a little and use the same terminals, but only if I can open them up clean and it works out. The black clips seem to still be in good shape...

Attachment 1729

Attachment 1730
Alternator end of harness.


Attachment 1731

Attachment 1732
Wires leading to "+ box". Looks like one is slightly larger ?

Attachment 1735
Fried "+ box".

I hunted high and low for something to replace + box. I had no luck locally. Anyone have any suggestions ?

If not, I found a few a few types of junction leads online. I may order something like below. Does it matter what kind of junction to get?

Attachment 1733


Thank you for any help! Respec!

As far as I know the + box is still available through Toyota. I ordered a couple last year and there was no problem getting them. They are Toyota part #82671-28020 & go for around $15 each. You can get the 3-wire Denso plug on eBay: http://www.ebay.com/itm/Alternator-R...3D161823358577. It comes with enough wire to splice into. Butt connectors would work, but for this location I would recommend solder & shrink tube.

I have the special crimpers for putting eyes on the bigger wire & I could easily fabricate these. If there's enough interest I could probably make up a few and sell to anybody who wants one. Toyota was selling these for around $65 before they dried up...........anyone willing to pay $50 each for ones made by me? If 10 or more people want one I'll make up a batch. Tim

I picked up one of these a while ago while doing a harness repair.

The plug fits right into the alternator, and I just cut out the plug end you have pictured and replaced it with a few different good quality quick connects.

Works great so far!

I have a trusted source at toyota that digs for me when parts are needed. No luck on the box. He even dug pretty deep to see if he could find a harness laying around somewhere. No luck. Not to say box is not out there, he just couldn't get one for me.:?:

I'm on a tight budget so I've got to try and build my own using what I can from old harness. If I had the cash Tim, I'd take 2 or 3. Thanks for being willing. Tim I bet you'd make some good money if you had your own online store going.

Yeah, I'm not so sure I'd make money unless I had big buying power. I checked into some of the materials and found some to be quite expensive. The high temp braided loom that covers the harness goes for almost $4 per foot! (and that's if I buy 50 or more ft at a time). The Denso plug goes for around $12, then there's the other Denso style plug that goes to the van harness (didn't look that one up yet) the wire, terminals, and the boot. Not including labor, to make a reasonable copy (without the oil level sensor part) would likely cost me $40+ each. After getting that far I decided it's not worth my time. Next time I need one I may make a few and put them for sale here (in the classifieds), but that won't be anytime soon. Tim

I ordered the 82671-28020 about a month ago, sitting on my desk as we speak, just waiting for install.
Now I WISH I had only paid $15 for it, probably best if we don't talk about that aspect, at all.
I do tend to lose it whenever we start talking about Cdn parts pricing.

Your guy should be able to get one.
BB

I had no problems, but it's been almost a year since I got mine. More & more I find things are here today & gone tomorrow. Canada does a lot of things better than the US, but they suck on pricing parts. At lease we do better on that here in the US............IMO we're paying about 3X too much. Thanks for sharing as it takes the sting out knowing that you Canucks are paying 8X too much :lol:. Tim

Hey Tim,

I thought there was an older thread where you had found an outfit that specialized in rebuilding wiring harnesses.
Is that the case or am I thinking of something else?

There's a member here "wirewrkr" that has a business rebuilding motorcycle wire harnesses. He had posted a link to his website & this type thing looked to be right up his alley. He hasn't been around for a while though. I just checked his website and see it's gone now too. Maybe that's the thread you're thinking of? Anyhow, I hope he's okay & still has a van. Tim

I love these forums..but I sure wish I didn't have to spend so much time here. I've dug through so many posts and I just can't seem to nail what's going on with my van.

I'd like to post the nice pictures I took of my harness build. But I'm not so sure I did things correctly.

Been dealing with electrical issues for a little while now. (hope this is ok to ask this here in this thread...) I thought it was alternator issue to begin with. I've been through 3..or 4 now. In past 3 months or so. No the steering pump is not leaking. Alternators have been clean. The last one the shop said it was faulty and they told me they would rebuild. I believe it is a Denso. Put returned alternator back in.

In the mean time, after doing research here, realized my van did not have FL 2.0L OR FL 0.5G ! Weird that I actually drove van for about a year with no issues until now. SO, I replaced FL 1.25B, and added the FL 0.5G and FL 2.0. I figured I might as well build new harness as well. So I fabbed together new harness and also put in new junction box to replace burned "+ box"...got everything buttoned up. Van started and ran nicely, no xmas lights. Battery terminal initially showed 13.8 v at start up. Drove for about an hour then things went dim and barely made it home. I took a small video I can post later, showing all the lights flickering everywhere as I idled and rev'd the engine. Van sat overnight. In the morning van won't start now.

I'm stumped. Could it be that i did not build harness proper? Any help is much appreciated. I'm about to set everything on fire at this point :pissed:...

My main issue was with on-going intermittent no cranking but also had issues with charging circuit.
I too was missing the 2.0 and .5 FL's.
I went through 2x FL1.25B and while doing some body work had occasion to pull the main harness.
I started at the FL1.25B and worked backwards then I found a failed factory splice which caused me to look further.
In the end I cut out a zillion factory splices, replaced about 5 miles of wire (essentially everything in the engine bay area) I found issues with the wiring for things ranging from start and charging circuits to engine management to lighting to you name it.

The wiring for FL1.25B disappears into the main harness behind the battery, along the frame rail and up into the engine bay. There are several wires that splice off all the wires to that FL (alt, starter, 60AMP fuse, +ve power post………).
While I am not yet able to claim that I have fixed my issues (it came off the road for a 2 week repair, 7 months ago and is still apart :no: )
I am truly expecting things to be a WHOLE lot better.
Silver wires (copper depleted) are not very conductive, nor are green splices.
There are pics in the other thread ("xmas lights continued", IIRC)

I would go back over the repairs you've already done, just to make sure something in the alternator harness didn't come apart but if that doesn't show any smoking guns, also check to make sure the "good" alternator isn't to blame.
But if all those check out fine, I would then dig further into the main harness.
BB

PS - I just looked at your pictures again and realized that the wiring that can be seen looked very similar to all that I have replaced.
What I found was key to the whole procedure was that any wire that felt stiff or looked "dirty" (at first I just thought it was dirt) turned out to be damaged wiring.
After a while I stopped cutting open insulation and just replaced anything that was stiff, occasionally I would double check what I had just cut-out, but even stopped that after a few times of confirming my suspicions.
I also found that if one part of a circuit had issues, I was almost guaranteed I would find more further downstream, hence the rec to dig further into the harness.

Thanks burnt. I saw your other thread and I don't think I'm willing to do that kind of work. Would rather push it off Big Sur and let it sink... I'm hoping I find a mistake in my harness build or my fusible link work. Or hoping the alternator my shop "fixed" is not actually fixed.

Jumped the van this afternoon and it runs without being on jumper cables. Volts at battery are reading between 9 and 10 volts. Battery reading 11.5 or so when not running. Anything else anyone knows that I can test while running, or not running to rule out, or narrow down issue?

Anyone have a photo of the upper connection on the alternator harness where wires connect?? I have a feeling I might have not clicked the wires into the connector in their proper location...

I'll post pictures this evening to see what you all think...

Ok. I may have found my issue. I used a life line and phoned a friend. Got a picture of the upper alternator connection. I suppose I could have just looked at the male end of upper connection in van to realize my mistake...:doh: doh! When I built the harness, I clicked the wires into the plastic clip wrong. I swapped the "IG" Terminal and the "B" Terminal. "IG" Terminal is the ignition switch to turn the regulator on. And the "B" Terminal is the Grounds and warning lamp terminal.

Not sure if this is going to solve all my problems. But I've fixed the harness and proceeding.

i suffered an age old symptom of red battery and orange engine check lights flicking on/off on the dash, engine stuttering thought it was a bad earth or something, first i checked all the fuses under the dash and in the engine bay, found none blown but the red battery light and orange cel still show on dash, usually means dead battery or alternator. i had recently disconnected my alternator so i thought i would look and see if i made good connection with the plug. it was plugged in tight but I pulled back the heat proof sheathing and found this:

er http://i295.photobucket.com/albums/m...psmzxq4mxp.jpg

i guess over the years of people working around the area the cable got frayed, as luck would have it it frayed right next to the plug so i thought i was screwed, and would have to find one at a junk yard with long cable.

on closer investigation of the oem plug i removed the rubber dust cap on the back and found using a small screwdriver you can actually release the spade pins from the plug quite easily, they have a little spring latch (barb) where the green arrow shows, just push it in with a tiny scredriver from the open end of the plug and the pins pop out with a little tug.

http://i295.photobucket.com/albums/m...pslvdy0n83.jpg

bad luck went to good luck... my local parts store had a supply of 2/3/4 pin connector plugs and they use exactly the same 1/4" latched style pins.. so i stripped the pins from the plug, attached some longer wire and they clicked right into the oem alternator plug. suprising!
put the rubber dust cap back, just soldered and shrink wrapped the new wire connections and taped after, no trip to the junk yard searching for old looms and plugs. :thmbup:

http://i295.photobucket.com/albums/m...psrs5egf6e.jpg

http://i295.photobucket.com/albums/m...psqpyc33s6.jpg

Nice work, Adam! Thanks for the write-up and photos.

Hi Yall,

Had a rough night tonight...

1st, I noticed the christmas lights on the dash of my 89 van. Before I used to just play around with the positive wire that goes to the alternator and snug it in more and it would go away. It is broken and doesnt clip in, thats probably due to someone yanking it out in the past. But anywho, this time I tried to push it in when that happened and the lights were still on. I had a friend look at it and he saw that the positive wire sparked pretty bad when he touched it and said its grounding out. He said that wire needs to be fixed and thats my problem... Has anyone ever repaired this positive wire? The plastic positive post on the engine bay looked a little melted. I doubt my alternator has gone bad because the ps pump is not leaking...

To top the night off I had the van towed back to my flower shop and I had a couch inside the van. While the van was being towed i guess the couch moved around and It busted my rear left window while it was being towed and ofcourse the tow company explained to me that they are not liable for that.

I thought Tim had a nice write up about alternator harness issues but can't find it. Maybe he'll chime in.

I'd focus on repairing the loose connection for sure. If it's moving around and sparking while you're driving you might end up with a burnt up van.

Check that your alternator is charging.... voltmeter on the battery should read over 13.5 volts while running.

my positive connection failed and melted the little black terminal box.............I cut the two eyes off the wires ,stripped about an inch of wire jacket off and used a splice cap/marrette .....a big blue one and packed a little blob of silicone in the end......ask an electrician for one maybe......pre twist the wires together first before twisting on the cap

Maretts have absolutely NO place in a vehicle, especially in a place that carries that kind of current.
The pos. post is still available from Toyota and isn't crazy expensive.
It WILL solve all your problems and save BBQ'ing your butt.

BB the splice I did with a marette has been good for 5 years ....no problem.....I used a little anti oxidant goo also for good measure[nolox]...marettes don't carry current ,just hold the wire......I rather rely on a marrette than a pair of crimped stakon eyes......I thought about using a split bolt but didn't like the idea of the electrical tape melting in the heat.

Hey Nik
I was always taught that Maretts don't like vibrations and can't be trusted to hold things secure.
I am also not a fan of crimps for most applications (attaching fusible links would be the exception) but prefer to solder and shrink.

I like to keep my positive wires well secured, and see no sense in doings things part way, but am glad it works for you.

Given that OEM parts are still available and affordable, I don't see the point in taking chances.
BB

To follow up on this..It's been a while and the DIY harness build and fusible links and work I did has held up fine. The issues I continued to have were due to aftermarket alternators. To date I think I've gone through 5 alternators. I kept having to swap out ones from Oriellys till I found one that worked longer than a few weeks. Almost each failure happened while on long trips (100+ miles) while driving for hours on end. Maybe the long heat and load on these things frys them. Ultima I think is the brand Oriellys uses. These "lifetime warranty" alternators are trash in my opinion and they don't fit right. What I ended up doing was finding an original denso/toyota alternator in a junk van with somewhat low miles and used that instead and I have the last one I bought on hand as a back up. What I'd like to do next is buy the internals for the og denso and keep that one going strong. Here's the thread timsrv outlines that- http://www.toyotavantech.com/forum/s...ght=alternator

Quote:

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Originally Posted by timsrv

Here's a diagram I marked up with the wire colors used on van harnesses:

http://i8.photobucket.com/albums/a23...pse28810a5.jpg

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My charging wire (+box to the alternator post) is actually two 10g-ish wires with separate eye connectors to the alternator post. Can someone please confirm that this is the stock setup and not something shady from the PO? I discovered (after much popping and smoke until I unhooked the batt ground) that indeed a 2nd wire (with a missing eye connector) was partially exposing itself out of the harness sleeve. I'm frustrated I didn't catch this earlier, and am concerned that I may have fried a thing or two as a result.

Pos box should have 2 wires with ring ends.
One heavy wire coming from the battery, the 2nd heavy wire goes off to the alternator.

The factory wire is fairly light gauge and I dont remember if it was a double wire or not.
When I replaced mine I used 8g wire with soldered ends.

Thanks, Burntboot. Looks like mine is similar to Ratatouille's in post #44 (likely 10g and a second 12g or 14g wire). But since the repaired wire is now a tight fit and I foolishly broke the +box in the process, I'll be upgrading to an 8g this weekend.

Quote:

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Originally Posted by Burntboot

Hey Nik
I was always taught that Maretts don't like vibrations and can't be trusted to hold things secure.
I am also not a fan of crimps for most applications (attaching fusible links would be the exception) but prefer to solder and shrink.

I like to keep my positive wires well secured, and see no sense in doings things part way, but am glad it works for you.

Given that OEM parts are still available and affordable, I don't see the point in taking chances.
BB

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well it is 2020 and big blue marette is still hanging in there haha

My alternator plug had been causing me some troubles. I noticed the last time I changed the alternator that the plug/wires were on their way out. I rolled with it, but soon after started getting christmas tree lights intermittently. one time, which was on a drive from SF to SD, just over the Grapevine, the dash lights came on solid. I pulled over (in the dark) and managed to discover that if I bent the wires in a certain direction, the dash lights would turn off (completing the circuit). I ended up using two zip ties around a hose to keep those alternator wires bent towards that sweet spot. Exactly like when your cell phone charger cables starts to crap out and you have to bend the wire to make it work. This was a quick fix that ended up lasting the rest of the trip to SD, the drive back to SF, a month of puttering around town, and a drive back to SD! A few weeks after that last drive to SD is when it really started to get wonky. The sweet spot was almost nonexistent at that point.

ANYWAY, I finally got around to pulling the harness out. I replaced the plug, and soldered those new wires that came on the plug, onto the existing wires in the harness. I had to trim back a little bit to get to the section of wire that was still healthy. Shrink wrap and E tape, back in biz.

While doing this I also re-seated the + wire to the alternator. The spade that is on there, didn't sit completely on the nut of the new alternator, so I put it on upside down, which ended up making a WAAY more solid connection.

Result - brighter lights, what seems to be a little more pep in the step, and...better gas mileage?? When I got the van, the coil was bad. I can't help but to wonder if these wire issues had been an issue for quite some time leading to other electrical concerns / problems.

Anyway, I barely took any photos because my hands were all gunked up. But I'm stoked it worked out!

What are the wire gauges to build a new whip from alternater to harness please?

I m having some alternator issues right now. Want to do a thorough test of the wiring. Continuity from all the wires in the harness back to the connector. Does anyone know the points behind the connector I can test for continuity? I m particularly interested in IGN circuit on the alternator connector. I attempted to test for voltage on the ignition wiring and found none. Any suggestions would be helpful.

This is a really dumb qeustion but hypothetically... if the sense wire was cut off or perhaps, entirely missing... what symptoms might you have?

Read the 1st post in THIS THREAD, particularly the part describing the FL 0.5G fusible link. Tim

Sweet, I brought it into the shop and they went through 6 warranty alternators. Where might i find this sense wire?

:cnfsd: Did you read the other thread? What was the charge voltage on the other alternators while they were functioning??? Is there a power steering leak getting on the alternator? Are you using a genuine Denso alternator or one of those cheap aftermarket rebuilds? I'd also recommend searching the site for the thread "alternator woes" and read. Tim

Some alternators out of the box were fine for a short while, then others would come out of the box with charging voltages of 15-17.8volts. The 7th one. Which is currently inside my van seems fine. But thats because after the 2nd alternator, i got fed up and brought it into a shop. When i first arrived, i told them to inspect wires behind the dash and the fusible links. After the 5th one I told them again and they did. Now it charges. But it doesnt seem like it actually knows where my battery is at in terms of charge. And I can't find the area on my van that this sense wire should be.

The info you're after is well documented in those 2 threads (and others). Tim

i appreciate it. they've been very helpful. BUT I cannot for the life of me locate the sense wire (0.5g) fusible link. maybe that's my problem.

The 1st thing you should do is unplug the round alternator connector and check voltage at the white sense wire. If you see battery voltage here the sense wire is hooked up and there's no need for further investigation. If however there is low or no voltage here, that's a problem that needs to be investigated.

Here's a picture from the fusible link thread:

http://i8.photobucket.com/albums/a23...v/IMG_0168.jpg

The 0.5G fusible link is the little yellow cylinder to the right of the battery. This connects the battery + to a white wire that goes to the "S" terminal on your alternator. Even if yours is there and is hooked up, it's very possible it's corroded and/or not making good contact. Over the course of 30 something years, it's also very possible somebody broke or cut this out, but the wire should still be down there going into the harness. If you find the end of a ~14 ga white wire down there that's cut/broken, it's a good bet that's it. If you find that wire, use a meter to verify continuity from it to the alternator harness "S". Assuming you see continuity, hook it up to the Battery positive terminal via an inline fuse. Based on wire size, I'm thinking a 10 or 15 amp fuse would be appropriate. After hooking it up, use a voltmeter at the "S" terminal again to verify you fixed (should see battery voltage here). If there is still no voltage or you can't find the wire, you could always run a new one. Tim

PS: Due to age and extreme conditions, it's also possible wires in the alternator harness are compromised. Due to years of vibration and flexing it's not uncommon for the last few inches of wire going into the alternator plug to become broken and fractured inside their insulation. The worst part about this type of degradation is connectivity is often intermittent. Intermittent problems are hard to diagnose, so if you think this is a possibility you may opt to simply replace this part of the harness. Even though the OE alternator harness is NLA, as shown earlier in this thread you can still get the round plug with wires from aftermarket sources.