BJ 24v bad electrical design?

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I was installing my voltmeter, during the install i decided to remove the dash pad center light to clean it. when i removed the light housing it was stamped "12V" on it. I was planning to replace the bulb with one using leds that i have. So when i saw 12V on the housing i was puzzled. I thought that only the head light were 12V. Well i was wrong, after checking the electrical scheme. I realized that the cluster light and the dash pad light also use 12V. Now no wonder why even on a stock rig batteries would not last very long. bad design, why didn't they go with 24v blub?

Granted some will say we are talking about 20-30 watts here, still it is draining more current on the right side battery.

Having known that i would have wired all my autometer lights to those! in fact, i'm thinking seriously about doing this, all the gauge light will dim just like the dash light. Isn't that sweet! But put more unequal current on the right side battery. Or install a new dimmer just next to the head light knob and wire all dash light to that one, and it would be hooked to the converter.
 
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keep digging there champ. There's a wee voltage drop down converter for that light and the one in the glove box (if its still there) to provide 12v power. I don't believe there are any others that should be twelve but I haven't ripped all of them out recently. This converter lives near the passenger left foot area near the heater controls and is half the size of a deck of cards. Its got a green cylinder on it.
It is NOT wired up improperly. The headlights use a completely different set up. BE CAREFUL IF YOU CHANGE THEM. Amazingly Toyota is a bit ahead of you on this one. Alternatively you could pull the converter and replace with 24v after this. I'm going to guess that it was a serviceability issue for the reason they went this way.
Good luck and let us know what you come up with.
 
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keep digging there champ. There's a wee voltage drop down converter for that light and the one in the glove box (if its still there) to provide 12v power. I don't believe there are any others that should be twelve but I haven't ripped all of them out recently. This converter lives near the passenger left foot area near the heater controls and is half the size of a deck of cards. Its got a green cylinder on it.
It is NOT wired up improperly. The headlights use a completely different set up. BE CAREFUL IF YOU CHANGE THEM. Amazingly Toyota is a bit ahead of you on this one. Alternatively you could pull the converter and replace with 24v after this. I'm going to guess that it was a serviceability issue for the reason they went this way.
Good luck and let us know what you come up with.

On a 70 maybe, not on a 40-42. look a this electrical scheme closely. From the tap between the battery on the left to the dimmer relay, then the dimmer sw and light control switch.

http://www.ericleblanc.com/gallery/g2data/albums/Eric/landcruiser/divers/electric/electric bj40.jpg

They must have corrected this on the 70.
 
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Are you sure the cluster lights and gauges are 12v I have just recently changed my lights on my gauges and used 24v,are you referring to a Bj42 CDN version.
 

Stone

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My suspicion is that Toyota probably HAD to change some of their lamps to 12v to fulfill some sort of Canadian Government requirement. :rolleyes:
 
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Are you sure the cluster lights and gauges are 12v I have just recently changed my lights on my gauges and used 24v,are you referring to a Bj42 CDN version.
I did not put the cluster apart to test the voltage. But when i turn the knob, the cluster light dim with the dash pad light. Therefore i assume they are on the same link. And it would match what is shown on the electrical drawing posted above.

Yes my truck is a CDN BJ42.

NOTE: the dome light next to the door, is 24V.
Resize of IMAG0027.jpg
 
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lostmarbles

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My suspicion is that Toyota probably HAD to change some of their lamps to 12v to fulfill some sort of Canadian Government requirement. :rolleyes:
x 2

The wiring in 24V Canadian cruisers of this era appears to be "unique to this market" and certainly didn't represent "best practice" (in terms of "electrical design" for that period) in my view.

It appears that the Canadian bureaucrats (no doubt thinking they were acting in the best interests of private Canadian motorists) asked (or maybe FORCED through legislation?) Toyota to use "the 12V bulbs that most private motorists are familiar with and can obtain easily" in these 24V cruisers. And so Toyota conformed - but didn't do a good job of it.

I suspect Toyota probably viewed the request with the contempt it deserved and gave the job to a "junior engineer" to perform. :D


:cheers:

PS. I've arrived at this conclusion from studying various threads in the past. (Mainly relating to the headlight wiring of 24V canadian cruisers of this era.)
 
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Try putting a voltage tester on it,I have replaced that bulb and the one under the ashtray and both bulbs were listed as 24v through Toyota one of them no longer available,I have tried putting a 12v bulb in only to have it blow,it may be possible they used a 12v part by mistake at the factory but has no effect if the power source is 24v and the correct bulb is 24v.
 
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Try putting a voltage tester on it,I have replaced that bulb and the one under the ashtray and both bulbs were listed as 24v through Toyota one of them no longer available,I have tried putting a 12v bulb in only to have it blow,it may be possible they used a 12v part by mistake at the factory but has no effect if the power source is 24v and the correct bulb is 24v.
I checked and it is 12V current going there and the bulb is a 12V 3watt
 
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My Canadian 83BJ42 is also just like eleblancs. The dash light is stamped 12v.
Eleblanc although i noticed this same thing a couple years ago i never thought to check the dash cluster bulbs. Have you actually tested there voltage to verify that they're also 12v? If so, that would be cool as i know there are led's that the FJ guys replace them with.
 
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My Canadian 83BJ42 is also just like eleblancs. The dash light is stamped 12v.
Eleblanc although i noticed this same thing a couple years ago i never thought to check the dash cluster bulbs. Have you actually tested there voltage to verify that they're also 12v? If so, that would be cool as i know there are led's that the FJ guys replace them with.
I have a other cluster lying around and the bulb are 24V. Next time i pull my cluster on the truck i will check voltage there. I guess it is 24V. I also guess i don't fully understand the electric drawing. Anyhow, when you turn the dimmer knob, the cluster light (24v) dim and the dash pad light (12v) also dim! Go Figure!
 

Greg_B

 
 
 
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I remember buying those for my 1981 BJ42 to replace burnt out bulbs in the dash area. It's under its winter tarp, so not going to access to see what is stamped on the housing...but I know from my frame off that all the dash bulbs I used in the dash area are 24V. I'll check what EPC says too, when time presents.
 

BreckenridgeCruiser

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I just checked the EPC (too cold for a nightime trip through the rig) and my heater control light is 12v also; and it's a JDM rig. So it may not be a canadian thing if japanese trucks have 12 volt bulbs there too... Really odd. I wonder what the rationale is.

K
 
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Now you guys got me second guessing mine,I have both JDM's and CDN 40's I'll be going out and pulling mine to see what current they are delivering,I would like to trace it through to see were it gets it supply from and how many amps ,this may be a good power source for 12v if it traces past the light switch and dimer.
 
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I discovered a couple years ago through another member that has a Can 83BJ42. Breckenridge is right as both the dash and the lower heater control knob lights are 12v. I initially thought maybe both were wired in series w/12v bulbs. However there not. So i figured there must either be a small drop resister inline with these lights or they truley are sourcing a 12v tap somewhere. Perhaps they're thought was that it was such a small draw it would be insignificant. Curious as Eleblanc noticed that they do however, dim with the cluster circuit. I considered using this 12v light circuit when wiring up th etach,pyro, and boost gauges as they all have and require a 12v source for lighting. Not knowing enough about this circuit i opted for 24v relays and used the solar converter for power. Interesting post.
Eleblanc- Like yours, my dome/cab light is also 24v. Slightly bright at best. Have you any knowledge as to the coorect 24v LED to replace the stock one with. I'm sure it would be far better?
 
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I discovered a couple years ago through another member that has a Can 83BJ42. Breckenridge is right as both the dash and the lower heater control knob lights are 12v. I initially thought maybe both were wired in series w/12v bulbs. However there not. So i figured there must either be a small drop resister inline with these lights or they truley are sourcing a 12v tap somewhere. Perhaps they're thought was that it was such a small draw it would be insignificant. Curious as Eleblanc noticed that they do however, dim with the cluster circuit. I considered using this 12v light circuit when wiring up th etach,pyro, and boost gauges as they all have and require a 12v source for lighting. Not knowing enough about this circuit i opted for 24v relays and used the solar converter for power. Interesting post.
Eleblanc- Like yours, my dome/cab light is also 24v. Slightly bright at best. Have you any knowledge as to the coorect 24v LED to replace the stock one with. I'm sure it would be far better?
I never was able to find those dome blub, i had to order something like 10 led bulb from a Australia supplier. But they do not last, brighter yes. If you search in this section for post from me a the word "bulb" or light you will find a post maybe 2 years old on my bulb replacement.

I never notice but you are saying there is a light in the heater control temperature? I'm not sure i understand what is the "lower heater control knob"
 
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If the dash light are 24V, heater control and dash light 12V, this section of the electrical drawing make sens, and the voltage drop would be acheived by a resistor that i do not know where is located. And hooking up anything else is not a wise idea.
heater_control.jpg
 
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From the diagram i do see the resister, that's possibly the drop. The knob that flips/switches the heater flap on the heater(left lower side section of heater is illuminated by a light box that contains the same bulb that the dash pad light uses. This too, is 12v.
 
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I have never replaced the dash pad light or the light for the heater, but according to that wiring diagram one of the headlights is powered from a battery tap and the other one from a tap on one phase of the alternator. However, since both headlights work without the engine running I am wondering if the wiring diagram is even correct?

There is at least one resistor on the side of the glove box for the lighter, and if my memory serves me correctly there is also another one I believe for the lights. At least on my '79, but it is a long time since I looked.

I have tried 12V lamps in my cluster, they are nice and bright for the few minutes they survive.
 
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AJAEbj42

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This is my 81 CDN BJ42.

There is a 24V bulb in there now (Thanks Greg!) as there wasn't one before. I'll put a volt meter on it this afternoon. The bulb goes brighter and right to 'off' when I turn my dimmer switch on the headlight knob.
IMG00060.jpg
IMG00061.jpg
 
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