HJ60 24V Alternator (charging) issue

[Biche]

Currently my 1987 HJ60 (CDN specs) does not charge my batteries. went to Yankee Toys Fall Gathering 3 weeks ago, 5 hours drive back home and parked it since. The cluster voltmeter tell me it's about 24V (which usually read higher when running) and drops when using my headlights or A/C blower fan.

What I've done:

• Checked the voltage at the battery: 24.8V when stopped and when running.
• Checked the voltage from the alternator top terminal with ground and also got 24.8V when running
• I've done a quick check of my wires harness but nothing seems out of the ordinary, but may need to re-check them when time permits.

During the Fall Gathering we have gone through a 4-feet deep water crossing but was able to bring back the truck back home the day after. Can water damage the alternator? I don't think the water really got to the alternator since it's was a short dip.

What can I check next? Can it be the brushes? How can I make sure? The FSM didn't help so far.

 

[sved]

Do you know for sure it is not charghing? I mean, did you measure the output (Amp) with the engine running,and all lights,blowers etc switched on.(around 15 to 17Amp)

Do you have a slow cranking engine,or does it start normal?
Charge warning light on or off when engine is running.?
Fuel sedimenter warning light on or off when engine is running?(Charge light relay)

Even when the battery's don't need charging you should have at least around 27V output measured on the B terminal and the 24V battery side when the engine is running.
So your voltage seems a little low.(could be the IC regulator that needs replacing).

 

[Biche]

Based on the cluster voltmeter, I'm pretty sure I'm not charging as it lower than usual and drops when I put some load on it.

I was sure where I should put my multimeter to measure Amp, so I didn't check that.

Cold, it looks like it was harder to start but I didn't really notice since I didn't know that I may have charging issues, but when the engine is hot it's start like a charm.

No lights for now, I guess I still have enough juice. I hope the regulator on my alternator is the external version.

 

[sved]

If you have the original alternator then i'm pretty sure you have the internal IC regulator.
External regulator sits on the left innerfender.

You really have to measure the amp to be sure what is going on.
If you have the FSM for 2H/12HT you can check it step by step.

 

[Biche]

Ok, I've got the FSM, just didn't looking at it.

Will check the FSM and report back anything I found.

Thanks Sved

 

[hj 60]

My gauge is about 28V also, but I think this was before the new brushes, now it is a bit higher (@2000 rpm 5th gear it is above the line for sure 29,5V or a bit more?)
sep 2012: (fuel gauge headache)
EDIT:this is also the 2013 state, @2000 rpm it is above the line, but it takes a little driving before it gets there, just revving the engine is not enough
I have no pictures of before brush replacement, cant find video of the gauges (was three years ago)
But I think the lights went on and then I fixed it: did not get stranded for sure, trialfix with plastic square removal worked perfectly while planning the repair.

If it stops charging the light should go on (Filterlight and red charging light)
The brushes are replacable, or if you have the original square plastic still there you can remove that and with the few extra mm drive another few months.

New brushes: 2 euro
These outlast the dynamo said the enigeer, very hard brushes.
hardly ever replaces tem.
27371-56070
denso, jndx32
cnd-ft313
5 x 8x28mm

624.2551.90
Replaces
Isuzu 5-81215-018-0
28.0 X 8.0 X 5.0
2 per set
JNDX 32 = FT 313

Terrible picture but at the higway with a telephone flashing in my hand could have endend with a 280 euro fine...
red 74 means next oil change @274000 km. TEMP: time to lower the radiator curtain (about 8 degrees C.)
@2000 RPM, 5th gear: snorring on vegetable oil 50% mix.

 

[Biche]

Thanks for the pictures and part numbers. My gauge was indicating about 28V like yours previously.

I'll try to get a llok at the brushes when the weather permit it.

 

[akifjanjua]

I am having very similar problem with like no charge on my 24v bj44.. I suspect a failed diode as I also see about 4-5v of AC voltage.. try checking with an AC voltmeter

 

[Biche]

I had some time today and checked the brushes, they were around 15mm long, so this is not the issue. I will have to find some extra wires and check the regulator.

 

[Biche]

I had some time today and checked the brushes, they were around 15mm long, so this is not the issue. I will have to find some extra wires and check the regulator.

Regulator is OK, I even try replacing it with a new one without success. I've seek expertise with 2 auto electrics shops, truck/alternator is not listed anywhere so they won't/can't work on my alternator, they've done some basic check on the alternator and seem ok but rebuilding and disassemble it would tell me more of the state of the alternator.

One of the shop told me the last time he saw one of these is when a guy using his 60 for plowing his driveway brought 3 of them to make a good one.

For now I will re-install the alternator to park the truck more conveniently and try to make it work over winter. I may try to source a replacement alternator or something else.

 

[yotahed]

Could be a couple burnt diodes. Will put out voltage but won't handle hardly any load. Sounds like the rectifier/diode pack is pooched.

 

[jetswim]

What js the status of each battery? If one battery is damaged it might affect things. When you tested was it at the cables or the battery posts? Not sure if it makes a difference but worth a try.

 

[yotahed]

X2 if the batteries arent the same brand/rating causes issues as well. And if one is on its way out it will take the other with it. Unhook both for a few days and see if one loses charge.

 

[Biche]

Both batteries have been changes about 2 years ago with 2 consecutive manufacturing serial number and they both kept the charge.

I've tested both at their terminal connection and from high positive and low negative terminal for the 24v.

 

[bj40green]

It doesn't matter at this point how good or bad the batteries are.
The output from the Alternator should be more than 24V and depending on the Voltage Regulator it should be around 26V at idle and 28.8V at higher rpm.
If one of the batteries is bad, you'll notice that at the center tap. The Voltage is not 50% of the charge voltage but higher or lower. Depends on which battery is bad.

You said that you measured 24V and that it also shows on the dash Volt meter.
It's possible that the Alternator is not charging at all and that you are measuring simply the battery voltage.


Did you check the "charge" fuse?
Did you check the fusible link?

We still don't know if you have an external or internal Voltage Regulator?

With external VR:
Do you have 24V on the IGN terminal on the VR when the key is in the "on" position?
If YES, Do you have 24V on the F terminal on the VR and the Alternator?

With internal VR:
Do you have 24V on the IGN terminal on the Alternator?


If it's not the Voltage Regulator it's probably one or more defective diodes on the rectifier plate(s). Any "car electric shop" should be able to test them. The FSM is very clear on the test procedure.

Rudi

 

[Biche]

Hi Rudi,

Yes, I do have the internal regulator. I've went through the FSM without success. But I did not check the fuse or the fusible link, I'll try to do that this weekend.

Both shops I went didn't want to open it to test it thoroughly as they can't source any parts from their supplier. One of them did some basic tests on it, but told me that I should open it to see what may be the cause.

 

[bj40green]

Oops, I forgot to mention the ENGINE fuse.

Rudi

 

[Biche]

I've check all fuses and unfortunatly they are all ok. The fusible links are fines too.

 

[bj40green]

Time to get the Voltmeter out of the toolbox.
Turn the IGN key to the "on" position.
Check for voltage on the IGN and the S terminal on the back of the Alternator.
Black test lead to ground. Insert the red test lead in the back of the connector. Don't disconnect the connector.


Report both voltages, please.

Rudi

 

[Biche]

Thanks Rudi,

I'll reinstall the alternator in the truck later this week and will report back my voltage readings.