Charging Glitch... I hate electrical Issues!

HammerDown

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Noticing that the dash battery icon light will 'at times' pulse on-off and also the dash 'gauge' will also slightly pulse towards the + side.

I put a meter on both batteries reading is 13.50 to 14.50 and at times 15 ... the reading is never steady and very irregular > > > but it is always in the + side of charging.

*** just over 3 years ago two new Bosh batteries... maybe one has a bad cell?

*** around 3 years ago I replaced the 70amp alternator (lifetime warranty from Pep Boys) don't laugh, the prior Pep Boys alternator lasted well over 20 years! (possibly failing?)

*** back then when replacing the alternator (and for giggles) I installed a NEW regulator, as soon as I fired the engine the battery light was steady-on. I reinstalled the very old regulator and all was good again, until just recently.

Feedback???
 

Big Bart

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Some thoughts -

1) Check the wiring on the alt. Top plug, back charge wire, and ground (Bolts to block.) on the alternator. Make sure all are clean tight and not loose. If your plug with the two wires is loose you could have erratic charging.
2) Pull the plug out of the regulator and check for corrosion. Check the wiring to the plug especially the ground wire. That ground wire has a connector between the regulator plug and the eyelet to the fender. That middle slide connector is problematic sometimes.
3) There is a fusible link that goes from the “Bat“ terminal an the alt to the starter solenoid on the fender well. Make sure it looks good and is not shorted out.
4) Make sure your connections going to your starter solenoid are in good shape. That is where the batteries feed wire and the alternator charge wire meet to let the alternator charge the batteries. So make sure they are clean and not corroded.
5) Your voltage regulator is supposed to regulate amount of volts the alternator puts out. So with your voltage all over the place it likely is the regulator that is the issue if your wiring is all good to go.
6) It could potentially be bad brushes, windings, or diodes in the alternator causing the voltage to vary. But that usually does not cause 13-15v volts of erratic up and down charging.

I would check your wiring top to bottom first. Then have the regulator tested at a parts store.(My guess is loose wire or the regulator is failing.) The stores with the computerized alt/starter tester can test regulators and alternators. If you cannot find some one to test, try a new regulator. If that does not solve the issue then replace the alternator. When You replace the alt you should replace the reg anyhow. (As you did back when but the new one appeared as if it was bad.). I would put a new one in this time.

If you do have a bad alt, many now upgrade to the 3g with the built in regulator. Search 3g on this site.

Let us know what it was.
 
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HammerDown

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Some thoughts -

1) Check the wiring on the alt. Top plug, back charge wire, and ground (Bolts to block.) on the alternator. Make sure all are clean tight and not loose. If your plug with the two wires is loose you could have erratic charging.
2) Pull the plug out of the regulator and check for corrosion. Check the wiring to the plug especially the ground wire. That ground wire has a connector between the regulator plug and the eyelet to the fender. That middle slide connector is problematic sometimes.
3) There is a fusible link that goes from the “Bat“ terminal an the alt to the starter solenoid on the fender well. Make sure it looks good and is not shorted out.
4) Make sure your connections going to your starter solenoid are in good shape. That is where the batteries feed wire and the alternator charge wire meet to let the alternator charge the batteries. So make sure they are clean and not corroded.
5) Your voltage regulator is supposed to regulate amount of volts the alternator puts out. So with your voltage all over the place it likely is the regulator that is the issue if your wiring is all good to go.
6) It could potentially be bad brushes, windings, or diodes in the alternator causing the voltage to vary. But that usually does not cause 13-15v volts of erratic up and down charging.

I would check your wiring top to bottom first. Then have the regulator tested at a parts store.(My guess is loose wire or the regulator is failing.) The stores with the computerized alt/starter tester can test regulators and alternators. If you cannot find some one to test, try a new regulator. If that does not solve the issue then replace the alternator. When You replace the alt you should replace the reg anyhow. (As you did back when but the new one appeared as if it was bad.). I would put a new one in this time.

If you do have a bad alt, many now upgrade to the 3g with the built in regulator. Search 3g on this site.

Let us know what it was.
All great suggestions and I will go through them;
This also occurred last winter, I unplugged-re plug the top wires to the alternator an I believe it helped.
Oddly it didn't do it all Tuesday and yesterday when I used the truck.
On this very hot Wednesday (today) after some 10 minutes of operation the bat light started again to pulse on/off and the gauge was pulsing to the + side... and it seems to follow RPM's. Then, it would stop for a while and then again act-up... I'll eliminate the batteries from the scenario as they don't mend themselves.
I didn't knoew some parts stores 'tested' regulators. My local Pep Boys does test batteries and alternators.
 

HammerDown

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Seriously, prior to installing a replacement regulator 'must' the batteries be disconnected?
Still haven't found the cause of the interment 'battery light flashing' and it hasn't happend for a few days of use but, I
I'll install on a new regulator.
 

rhkcommander

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I would heartily recommend swapping to a 3G alternator. You can jumper itself to itself so you only have to run one fat power cable to battery POS, then diagnosis becomes a lot easier versus chasing fuse links and old factory wires... the 130 amp alternator is common and a big leap forward over the stock 1G or whatever it is called.

I'm guessing you have loose wires/connectors if it's intermittent, especially on bumps down the road. 3G and one fat wire is a simpler fix and upgrade, good luck. I added a 150 amp reset-capable fuse breaker next to the battery positive on the hot line just in case.
 

catbird7

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By the way, my truck did the exact same thing you described with the battery light flickering. Ended up being the plug on top of alt. Well that's all gone now with the 3G swap. See pics, hope they help.
 

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rhkcommander

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I don't remember the green wire but I likely abandoned it. Great post @catbird7 !
I also used a resettable breaker instead of a bus fuse but it's all good.
 

ROCK HARVEY

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You checked the voltage at the battery, but have you checked the voltage in the cab with a voltage meter? I discovered today that my voltage under the dash is a full volt lower than my voltage at the batteries. I’m going to be checking/adding grounds this weekend and hoping that fixes the problem. Your charging system might be working fine and your gauge just can’t see it.
 

HammerDown

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You checked the voltage at the battery, but have you checked the voltage in the cab with a voltage meter? I discovered today that my voltage under the dash is a full volt lower than my voltage at the batteries. I’m going to be checking/adding grounds this weekend and hoping that fixes the problem. Your charging system might be working fine and your gauge just can’t see it.
Putting a volt meter on the batteries confirmed what the gauge was showing > > > a pulsing towards the charging side. But it only does this after it's been running for a bit of time.
 

HammerDown

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By the way, my truck did the exact same thing you described with the battery light flickering. Ended up being the plug on top of alt. Well that's all gone now with the 3G swap. See pics, hope they help.
Your truck flickered the bet light and OE volt gauge to the positive side?
So, that 3G alternator uses the OE mounting bracket etc or are modifications required?
 

TexasTruck

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I always wondered why my batteries would never last very long, crank speed on start was too slow and the glow plugs never seeming to work right for a first crank. I need to do this 3G upgrade.

I have a 30k lb winch on my truck so I need a little more than 100A.

I am having trouble finding that pig tail that loops back to the hot side and stator. Does anyone have a part number or link where I can purchase that piece and the resettable breaker for a 200A alternator?

Thanks
 

rhkcommander

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I always wondered why my batteries would never last very long, crank speed on start was too slow and the glow plugs never seeming to work right for a first crank. I need to do this 3G upgrade.

I have a 30k lb winch on my truck so I need a little more than 100A.

I am having trouble finding that pig tail that loops back to the hot side and stator. Does anyone have a part number or link where I can purchase that piece and the resettable breaker for a 200A alternator?

Thanks
I hit a junkyard for my plugs, Amazon has tons of options on breakers or you can show this to your local parts store:

250A Circuit Breaker Fuse Audio System Inline Holder Resettable for Car Marine Trolling Motors Waterproof https://a.co/fD3dvJn

Found the plugs too
Wire Harness Connector ASI 2G 3G 4G with 3G Stator Lead for Ford Alternator https://a.co/ek7qq8C
 

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