High Beam Indicator Not Working After Koito Install - LED Still The Fix?

CruiserTrash

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I'm still mentally sorting this out, but in the meantime....

What are the grounds for the gauge cluster? Is it exposed copper an the PCB that is contacted by a hold down screw? Is there a separate wire running to the body or back into the harness? I know the backlights things ground through the dimmer but where - physically - does that touch the battery negative post or the body?

Happy to do some digging on that this weekend but if somebody knows offhand that would be great.
 

OSS

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The battery grounds everything in the entire vehicle (except the starter and ignition) through that little wire connection to the body screwed into the inner fender next to the battery.
The body of the vehicle then becomes the ground for everything (except starter and ignition).

The electronics in the dash (along with the headlights) ground to a common little buss plug and that leads to a larger wire that is screwed into the driver’s side A pillar with a small ring connector.
The A pillar ground is nothing special. It’s just hidden and close to most things in the dash. Any section of metal anywhere on the body that has a threaded bolt hole is as good of a ground location than anywhere else.
 

CruiserTrash

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@OSS Thanks. I get the concepts, but was looking for that specific location.

If that wire is internally corroded it will provide additional resistance to DC current through the bulb - a second possible reason that only LED bulbs work, since it requires less current to operate. It could also explain why my indicator now works with an incandescent bulb but is very dim.

Here's the other thing - there's suspicion that the temp/fuel gauge spike issue is grounding related. I have that going on too. I may replace that wire and clean up the body termination end of things when I get some time and see what happens.
 

CruiserTrash

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@Seth S

Going back to your thoughts here. Since the Koito harness was manufactured for Toyota, wouldn't they have designwd it with the switched grounding principle in mind? I've heard this is the stock light harness from another Toyota vehicle, though that may not be true.

If it does convert the system to switched power with some tricky relay usage, then we might be in trouble.

Unfortunately the diagram of the Koito harness that was posted is ... not great. Good job Koito. 🙄
 
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I'm State Inspector in Texas,

Try plugging in one of the old headlights along side one of the koito lights and see if that makes the indicator come back on, if it does then you could maybe just throw a resistor of a specified resistance in the circuit somewhere and call it guud, or replace the indicator with an LED.

Technically you just have to have "a" light come on anywhere within the driver view when the brights are engaged to pass inspection, It doesn't have to be the OEM light, it can be any color and it doesn't even have to be securely mounted like the outside lights. the only rule for the brights indicator is it cant be "a glaring light." you could literally have a wire coming from your hood through your door to power the light. exceptions are the horn as it has to be securely mounted and blah blah blah.

Of course nothing beats fixing it the right way but if you're in a hurry to get it inspected it is technically legal.
 

Gretsch

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Thanks for this.

Because this truck is my daily and I am running out of days to pass inspection and need to have it inspected sooner rather than later, I ordered the ARB harness @OSS suggested and one of the LED lights. I'll try and fix this with the LED first and if it doesn't work I'll throw in the ARB harness. I would like to see still however what changes could be made to the Koito harness to just make this indicator work. If it turns out I need the ARB harness, I will have a Koito harness I can use to try and diagram how its put together. Thanks for all replies.
 

jerryb

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how much are you guys paying for relay set ups and wiring?

I'm only posting because I saw your thread on the right hand side talking about indicators and high beams. The lx and lc 100s have very different high beam indicators on the dash and how they're wired but similar in the switching and series vs parallel, daytime running light related.
I make a ton of harnesses for a certain reseller and lots of non nav set ups.
if someone wants to test out a set up for 60s I'm willing to try. I'm venturing outside my boundaries but it doesn't look difficult.
 

CruiserTrash

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@jerryb The kit from Koito (OEM supplier) is ~$55 from various vendors. It includes a harness that is a dead simple install, two round lenses, and two H4 bulbs. I think a lot of people pull the trigger because the price is very low and it's a huge improvement over the stock sealed beams - a nice value. Everything works except the high beam indicator.

A different kit that works with the HB indicator would be great. Hell, even a pre-packaged solution to just the HB indicator issue would be nice (which is what I'm working on 😉).
 
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@jerryb The kit from Koito (OEM supplier) is ~$55 from various vendors. It includes a harness that is a dead simple install, two round lenses, and two H4 bulbs. I think a lot of people pull the trigger because the price is very low and it's a huge improvement over the stock sealed beams - a nice value. Everything works except the high beam indicator.

A different kit that works with the HB indicator would be great. Hell, even a pre-packaged solution to just the HB indicator issue would be nice (which is what I'm working on 😉).

It should be noted that the new Koito lenses and bulbs will work perfectly well on the stock harness and the high beam indicator will work fine this way because its all 100% stock wiring and just newer more efficient housings and bubs. The add on harness just provides a new and more efficient power supply so there is less voltage drop to the headlights.
 

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@Seth S Yes, you could just swap the sealed beams for the H4 lenses and go. But you're right about the more efficient 12VDC delivery. It seems like every single 12VDC wire in these trucks is fairly undersized from an efficiency standpoint. They do their job and don't introduce enough resistance to get overly hot, but that's about it. Speaking of which the alternator-to-battery wire is next on my s*** list.
 
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Some reference photos:

1634316176170.png


1634316208269.png


The high beam indicator is the insert and twist to lock in place variety of bulb that gets its electrical connection off a printer circuit film on the back of the cluster.

that said I am sure you could pull the stock light out and replace with an LED and wire a fresh circuit that simply triggers off the high beam power.
 
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I think I would use the stock harness to trigger new relays just as all the aftermarket harnesses do. I would simply add a second relay triggered off the stock high beam signal so that when Hi beam is selected power is sent to the new indicator relay. If running an LED light likely need a resistor to drop the voltage down from 13 to 3.
 

CruiserTrash

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Thanks for the photos. This weekend I plan on check the ground wire from body to dash PCB. I want to check off any possible issues there before trying any "fixes".
 

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For what it's worth somebody is working on a daughter board that attaches to the stock dash PCB to solve the temp/fuel gauge spike issue, so my mind has been on the dash PCB anyway. Hopefully the fix for the HB indicator isn't so involved, but we'll see.
 

Gretsch

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It should be noted that the new Koito lenses and bulbs will work perfectly well on the stock harness and the high beam indicator will work fine this way because its all 100% stock wiring and just newer more efficient housings and bubs.

So to be clear here @Seth S you are saying that the bulbs you get with the Koito kit you get from Toyota (I forget the P/N now) can just use the factory wiring to light them? This might get me through the inspection bit without having to do much to the truck. Would still love to have this work with the Koito harness without all the games but I thought the Koito harness was different enough to not work with the factory wiring so it didn't even occur to me to try it that way. This would be great if true. Thanks for the heads up here. Always come through with great info.

how much are you guys paying for relay set ups and wiring?

I'm only posting because I saw your thread on the right hand side talking about indicators and high beams. The lx and lc 100s have very different high beam indicators on the dash and how they're wired but similar in the switching and series vs parallel, daytime running light related.
I make a ton of harnesses for a certain reseller and lots of non nav set ups.
if someone wants to test out a set up for 60s I'm willing to try. I'm venturing outside my boundaries but it doesn't look difficult.

The ARB wiring/relay harness that seems to make this all work properly is around $140 for reference. Prolly can find it cheaper if I looked around some. Kinda pricey to me.

Try plugging in one of the old headlights along side one of the koito lights and see if that makes the indicator come back on, if it does then you could maybe just throw a resistor of a specified resistance in the circuit somewhere and call it guud, or replace the indicator with an LED.

This idea did occur to me but I got rid of the original headlights after doing this kit, so I didn't have any to try. I think there is some do-dad available to mimic the headlight resistance folks have tried. Seems to work sometimes and sometimes not. Maybe this:

ca631151-6d6b-4d67-850a-3bddc66424f0-jpeg.2810760


Posted earlier in this thread. Results were not that great so maybe a different one would work better.
 
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So to be clear here @Seth S you are saying that the bulbs you get with the Koito kit you get from Toyota (I forget the P/N now) can just use the factory wiring to light them? This might get me through the inspection bit without having to do much to the truck. Would still love to have this work with the Koito harness without all the games but I thought the Koito harness was different enough to not work with the factory wiring so it didn't even occur to me to try it that way. This would be great if true. Thanks for the heads up here. Always come through with great info.
Yes. If you just plug the stock 3 prong connector into any H4 bulb it will work entirely normally. This was the very first mod I did on the cross country drive home from picking up my 60. Put a set of Hella housings and basic 55/60 watt H4 bulbs in. Everything works fine as does the indicator.
 

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Yes. If you just plug the stock 3 prong connector into any H4 bulb it will work entirely normally. This was the very first mod I did on the cross country drive home from picking up my 60. Put a set of Hella housings and basic 55/60 watt H4 bulbs in. Everything works fine as does the indicator.

Well thats great to know. Just tried it and like magic the hi-beam indicator works again. I can at least get past the inspection bit. Thanks for this info. I am a bit embarrassed I never considered this solution. Would still like to get the Koito harness to work but I can at least make my 60 street legal again and have confirmed that my indicator bulb works. Thanks again for this bit.
 
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Well thats great to know. Just tried it and like magic the hi-beam indicator works again. I can at least get past the inspection bit. Thanks for this info. I am a bit embarrassed I never considered this solution. Would still like to get the Koito harness to work but I can at least make my 60 street legal again and have confirmed that my indicator bulb works. Thanks again for this bit.
No worries. The electrical side of the business confuses a lot of people. The good news is that DC circuits are pretty simple to learn and most of the circuits in an FJ60/62 are really basic. I am not an electrical engineer but have had enough electrical courses and hands on experience to figure most automotive stuff out.
 

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No worries. The electrical side of the business confuses a lot of people. The good news is that DC circuits are pretty simple to learn and most of the circuits in an FJ60/62 are really basic. I am not an electrical engineer but have had enough electrical courses and hands on experience to figure most automotive stuff out.

Yeah I can usually figure out mostly simple DC stuff, but just assumed the harness converted things in such a way that the bulbs wouldn't work with the factory wiring. As in the harness was REQUIRED to make the new bulbs work thus making it different from factory somehow. I just never considered that possibility but I should have I guess. I actually kinda thought the plugs wouldn't physically fit the new bulbs to be honest. The Koito harness has those boots on the plugs and I just never looked inside them to see if they matched the factory ones. Another lesson learned here on Mud. Man so many lessons here. Thanks again for this clue.
 

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