24 Volt Alternator Help Needed....!!!

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Jan 23, 2008
East York, Canada
My HJ60 recently developed a charging problem. I'll try to describe what happens.
Before I start I have to mention that I have a 24 volt electrical system in my Cruiser.
Normally when I start the engine the voltmeter will indicate somewhere in the neighbourhood of 24-25 volts and the FILTER light will remain on. If I rev the engine to about 1200 rpm the FILTER light will go out and the voltmeter will go to it's normal indication of around 28 volts.
Recently when I start my engine the voltmeter will read just above battery voltage, say 24 volts or so. The FILTER light is on and also the battery warning light. Even revving the engine won't extinguish the lights like it would normally.
This morning I was thinking should I drive to work thinking maybe my batteries will get drained before I get to where I want to go. Strangely half way to work on the highway (engine doing about 2100rpm) the lights went out and the voltage went up to the normal charging voltage of about 28 volts.
Does anyone have an idea what can be the problem? Could it be a bad alternator? But it does seem to want to charge (sort of...)? Or is there a circuit of some sort that keeps the voltage low like when I first start the engine. And why, when everything works normal, I have to rev the engine slightly for the charging system to functon properly?
Help...!! :crybaby:
My 87 HJ60 always behaves exactly the same on startup, a little rev clears the lights and voltage kicks up to 28v. I, too, once had that situation where the filter light stayed on but it cleared after 10 minutes or so and never happened again.

I'll be watching for a definitive answer on this.
Same thing happens on my Safari but on when it is really cold (-10 and below) do I get the light staying on. As soon as it gets reved up, then it is fine. Even during the spring and fall the volts don't come up until the engine has idles for a few minute or until the engine has been idled up a bit. My guess is that it is like most of us older farts, it doesn't work to well until it gets a chance to warm up.:D
87 HJ60,

Sounds like the alternator is not putting out current. Here's a coupla ideas:

1) Confirm the alt drive belt is still there and the alt is being driven! (skipping the basics can lead to embarrassment)
2) Check the large and small power leads at the alternator to make sure the alt is connected to the vehicle and to the battery.
3) Perform an alternator output test. (you may need assistance or access to an inductive ammeter and full field jumper)
4) If you find the alternator needs brushes, great! You can buy those seperate without great expense.
5) If it all looks good, go find the "charge lamp relay" behind the left kick panel. Mine was well marked as noted in quotes. Pin test the relay and confirm the relay is receiving a charge signal. Repair or replace the relay if you find jumpering the relay turns the lights off.

Hope this helps the process.

Rick's post is excellent - and I'm willing to bet that the brushes are the culprit...
I confirmed that the alternator is turning with the engine and there's no slipping of the belt. It seems the alternator is charging, or at least wants to as indicated by the voltmeter in the dash. It reads roughly 26 volts or so. After driving for a while, say 45 minutes, the voltage doesn't drop so I'm assuming the alternator is charging. It seems there's something keeping the voltage slightly down and at the same time keeping the voltage warning light, FILTER light and I just noticed it also keeps the parking brake warning light on too.
Driving to work this morning the lights didn't go off after a while like they did yesterday. I'm still baffled about this.....
I'm thinking if it is the alternator brushes that are worn and bad that the alternator wouldn't be charging at all. Is this correct?
Rick mentioned the charge lamp relay. Can someone explain what he function of this relay is and if it's circuit relates in any way to the warning lights staying on.
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This evening I was doing a search on the internet and I found this article that makes me think that you guys were right about the brushes being worn.
Here's the link to the article:

4x4Wire - Replacing Alternator Brushes

I'm going to the Toyota dealership tomorrow and getting some new brushes. Once I get them I'll put them into the alternator. I'll post what happens for those that are interested.
87 HJ60,

Buying the brushes is fine, since they don't cost too much. Also, they are a wear item, so installing them won't be too much of a waste if they were not the culprit.
My previous post recommended a possible diagnostic routine to isolate (and repair) the problem. I offered the routine to you in order for you to eliminate guessing and unnecessary purchases. I personally take great satisfaction in deducing the exact problem and correcting it!
26v is too low for maintaining a 24v system, so it appears you do have a charging system fault as indicated by the lamps.
The charge lamp relay uses a charging output signal to close the relay, appling balancing power to one side of the lamps. This circuit creates an offsetting voltage at the lamps. The bulbs then have a 0v voltage potential across the bulb filaments and they go out. Since the indicated output of the alternator is low, I'd say the relay cannot be condemed at this time!
Yes, please keep us informed of your progress!

Both batteries are good. They're Optima red tops and only a few months old.
Anyways I removed the alternator from the engine and removed the brush holder from the alternator. Looking at the brushes there's only about 3 mm exposed from the holder. The minimum should be about 5.5 mm. Looks like the culprit.
I went to get a couple of brushes from the local Toyota dealership Friday. They only had one in stock. The other had to be ordered and should be in Monday. Cost of two brushes was $10.88 Cdn.
I'll get on replacing the brushes when I get the other one next week. I'll post my results next week.
Great! Let know how the rebrush works for you.


I replaced the brushes after coming home from work today. Since the alternator was already removed from the engine over the weekend it just took about 5 minutes with the soldering iron to get the new brushes on to the holder. I put everything back together and re-installed the alternator on the engine. Upon starting the engine the voltmeter indicated just battery voltage then after a few seconds everything went back to normal. The alternator is now putting out roughly 29 volts; no more filter and brake warning lights!!
Thanks for the help especially rchalmers. I'm always learning something new about Land Cruisers. Sometimes it's unfortunate that something has to break before you do your research about what's going on. But that's the fun of it. You learn so next time you know what's going on and also passing helpful info to others.
btw here's a picture comparing the old work brush to a new one. If you look closely you can see one of the old brushes in the holder still. Hardly anything left, only 2-3 mm of the brush protruding from the holder.
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Ya gotta love toyota!! 10.88 for two brushes!! I just replaced mine a few months ago, went down to the local auto electric shop late friday afternoon, I hold up a worn out brush and the guy lowers his cool one and says "is that out of a toyota? its a blah blah blah part number as his buddy reaches up and hands me a pair. I ask these guys how much (thinking I'll be running off to fetch a six pack) and the reply $1 but were closing and I can't be bothered to ring a dollar through, come back when you need some parts or a rebuild!
Those brushes are worth 50 cents and very generic!! if you live in a town big enough for a toyota dealer there's got to be an auto electric shop in town.

I am a semi-newbie to owning a Land Cruiser of my own (but my Dad has had multiple LCs for years). Anyways, I just bought a HJ60 and battery light is on, brake light is on and the filter light was on, but unexplainable turned of a few days back and hasn't come back on. Volt meter is reading 28 and have been starting it up above 60 and no troubles...
After reading the posts so far I am thinking alternator is probably a good place to start. Any other suggestions or input would be appreciated. thanks!
Volt meter is reading 28 and have been starting it up above 60 and no troubles...
Are you using the cluster gauge volt meter? If so, it's not the most accurate. Also check if both batteries are at the same charge level, this could cause one to overcharge. I changed mine recently and some voltages issues have disappear.

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