BJ75 Battery & Filter Light Issue (1 Viewer)

[theglobb]

Hey there, today was the first "cold" day where I live, dropping down to 36 degrees last night, I have no clue if this has anything to do with anything but yea there's that. As for the issue, it started today just as I had pulled out of my driveway and popped it into 2nd gear my battery and filter light came on simultaneously in my dash, as soon as I let off the gas to pull over it went away. Saw that there was no problem drove around for a bit and a minute later the issue happened again as I was in 3rd gear at a low RPM, as soon as I let off the gas the lights went away. I'll probably drain any water out of the filter tomorrow to see if that fixes the problem but the battery light coming on at the same time leads me to think it has something to do with the electronics. I also have an aftermarket water temp gauge that was working yesterday, but you guessed it, is no longer working today, seemingly as soon as the lights popped up for the first time. Is this a known issue or does anyone have any idea what could be causing it? Anything is greatly appreciated, I'll also attach a video down below that gives an example of it happening a few more times while driving.

 

[roscoFJ73]

Alternator or regulator?

 

[Gun Runner 5]

I wonder if those two lights share a common power source.

 

[theglobb]

Started it this morning at 34 degrees and both the lights were on from the moment it turned over, stayed on at idle, and when I revved it.

Alternator or regulator?

Those are both something I thought about, my car starts just fine though even with 1 functional glowplug at 34 degrees. Is there a simple way to test if either of them are bad?

I wonder if those two lights share a common power source.

That's what I was thinking, especially for the aftermarket temp gauge to go out as well. They gotta all share the same, just gotta track it down I guess.

 

[hj 60]

What my hj60 did:
Filterlight and red charging light went on.
Means brushes are worn out. Driving without belt gives red warning light only! (?why)

There is a 3 mm square between the brushes so I removed it and can drive about 1000 km/4 weeks.
The car stopped charging and then did not start, after replacing brushes and charging batteries it was ok.

brush assembly alternator hj60:
The plastic square part can be removed so when the charging stops you can remove the plastic square and drive another 1000km!
hj60:

 

[theglobb]

What my hj60 did:
Filterlight and red charging light went on.
Means brushes are worn out. Driving without belt gives red warning light only! (?why)

There is a 3 mm square between the brushes so I removed it and can drive about 1000 km/4 weeks.
The car stopped charging and then did not start, after replacing brushes and charging batteries it was ok.

brush assembly alternator hj60:
The plastic square part can be removed so when the charging stops you can remove the plastic square and drive another 1000km!
hj60:

Thank you so much! Kinda sucks that it's probably my alternator but at least now I'm pretty sure. Can't find any 24v in stock . Guess once my batteries die I'll be having to roll start it and shut it off with the EDIC haha. Appreciate the help.

 

[roscoFJ73]

Guess once my batteries die I'll be having to roll start it and shut it off with the EDIC haha. Appreciate the help.

Charge the batteries every night. Diesels dont use much during the day. If you flatten them all the time, you will need new batteries as well.
But you need to test the alternator and make sure thats the problem. A bad or dirty battery terminal can also do this.

 

[lacalvette]

You will soon find out that if your truck is from europe, the 24v alt will have an external voltage regulator... better take care of your alternator as they are hard to find. Or swith to an internal toyota or npr truck, people seem to have great success and not too expensive.
As speaking of alt, mine had a broken winding on the rotor, in the EPC, 24v from bj70,hj60 and bj75 seem to share the same rotor but in the FSM the resistance of the rotor is different if it's internally or externaly voltage regulated.
Since I damaged the tread on my rotor, decide not to send it to a shop and I use a rotor from a bj70? (Internal) and rebuild mine. Work like a Charm...

 

[theglobb]

But you need to test the alternator and make sure thats the problem

I have done some basic testing of the alternator and basically, it reads 24v all the time no matter what time doing, 23.8 if I have my lights on, but it keeps everything charged just at a lower spec of what it should be, FSM says 27-29. Would this be the regulator then?

You will soon find out that if your truck is from europe, the 24v alt will have an external voltage regulator... better take care of your alternator as they are hard to find. Or swith to an internal toyota or npr truck, people seem to have great success and not too expensive.
As speaking of alt, mine had a broken winding on the rotor, in the EPC, 24v from bj70,hj60 and bj75 seem to share the same rotor but in the FSM the resistance of the rotor is different if it's internally or externaly voltage regulated.
Since I damaged the tread on my rotor, decide not to send it to a shop and I use a rotor from a bj70? (Internal) and rebuild mine. Work like a Charm...

My cruiser is from Europe, originally sold in Belgium and then sometime in France before coming to the US. Where is this external voltage regulator located? I could only find where the internal one is in the FSM.

 

[BreckenridgeCruiser]

Worn brushes would reduce the voltage output from the alt... I'd replace the brushes first.

 

[theglobb]

Worn brushes would reduce the voltage output from the alt... I'd replace the brushes first.

I'll have it out of service to rebuild the knuckles sooooo I guess it'll be a good time to do that then haha

 

[lacalvette]

Mine is on the right side fender (right when sitting in car and looking to the front of the vehicle )(passenger on LHD), not far from the alternator, just follow the wire. There is really good info here on MUD how it work and how to test it.

 

[BreckenridgeCruiser]

I would definitely do it... You want to keep your alt healthy in a BJ since the alt/vac pump setup is hard to replace.

 

[roscoFJ73]

[

 

[theglobb]

Mine is on the right side fender (right when sitting in car and looking to the front of the vehicle )(passenger on LHD), not far from the alternator, just follow the wire. There is really good info here on MUD how it work and how to test it. View attachment 2487114

Awesome, thank you! My car is now reading 22-23v when driving around and I cant start it with the starter anymore... Fun times push starting it now to get where I want to go haha. I'll definitely take a look at the regulator, brushes, and anything else that could be screwing me over, after I finish rebuilding my knuckles. I'll keep y'all updated whenever I mess with it more.

 

[FJBen]

Not the same truck and I'm 12V vs your 24volt, but I had the same issue pop up on mine a year ago.

Are you getting any noise from the regulator when the lights are on? My regulator would buzz a little when the filter/start lights came on. Mine was rev/dependent as well.

Here's the page (18) where I'm troubleshooting it
Builds - 1988 BJ74 “Number 1”

tldr: I replaced the external voltage regulator and have had no issues since. Was like $56 + shipping from partsouq. I ordered alternator brushes as well, but haven't replaced them yet.

 

[theglobb]

Not the same truck and I'm 12V vs your 24volt, but I had the same issue pop up on mine a year ago.

Are you getting any noise from the regulator when the lights are on? My regulator would buzz a little when the filter/start lights came on. Mine was rev/dependent as well.

Here's the page (18) where I'm troubleshooting it
Builds - 1988 BJ74 “Number 1”

tldr: I replaced the external voltage regulator and have had no issues since. Was like $56 + shipping from partsouq. I ordered alternator brushes as well, but haven't replaced them yet.

Really??? That's great to know maybe it isn't my alternator! I hate dealing with electrical stuff haha. I'll definitely check that out as well and let you know if it's making some weird noise. 1 day ago I just went ahead and purchased an aftermarket alternator off of partsouq for my cruiser to use while I rebuild this one (if the alternator is the problem), either way, I wanted a spare one for when my buds and I drive to CA in the troopy this summer. Thanks for the info!

 

[theglobb]

Well I lucked out and it was my alternator, that I had already purchased, instead of the regulator. The aftermarket one had some funky elongated fittings for the vacuum pump so my dad and I custom made some hoses that will hopefully hold up for a bit. Now just to figure out how to rebuild the OEM alternator... If anyone comes across this thread in the future and wants to know what the problem is 100% before shelling out $$$, then do whatever tests you need to do to figure out if it's the alternator or regulator. Thanks everyone for the help and suggestions! Much appreciated