T1N Voltage Issue, on the road help

alexk243

KulAdventure
Driving my 2004 2500 on a road trip and I'm well over 2 days from home. Started having issues and need advice.

Has been fine for 30-40hrs of on the road driving. Parked for 2 hours, restart and the battery light is on, scangauge shows 12.2V with engine running. I drive it a bit, turn it off restart, drive, nothing.... I'm an hour from an auto parts store (Olympic National Forest) so I drive it using the rear battery and solar to keep engine voltage above 12v, which works. I pull into town after an hour of driving at 12.0-12.2v and I hear a whiring type of noise and the voltage jumps back up to 13.8 and everything is good to go...

I'm going to buy a new 150a alternator because NAPA has one and I don't want to get stranded.

What do you guys think?

KulAdventures.net
 

Aqua Puttana

Poly - Thread Finder
...

I'm going to buy a new 150a alternator because NAPA has one and I don't want to get stranded.

What do you guys think?

KulAdventures.net
Sounds like something that I would do.

Assuming the voltage is still maintaining 13.5 - 14.1 or so.
To me the question now is whether to just install the new alternator, or roll the dice. My inclination would be to replace the alternator. If the alternator is the problem, you are home free. If the problem is a connector/connection issue, it may be resolved during the parts change.

Changing the alternator under more controlled conditions has advantages over doing it wherever any future returning failure dictates.

To be clear, changing the alternator isn't a guaranteed fix, but it should eliminate some variables.

:cheers: vic
 

alexk243

KulAdventure
Sounds like something that I would do.

Assuming the voltage is still maintaining 13.5 - 14.1 or so.
To me the question now is whether to just install the new alternator, or roll the dice. My inclination would be to replace the alternator. If the alternator is the problem, you are home free. If the problem is a connector/connection issue, it may be resolved during the parts change.

Changing the alternator under more controlled conditions has advantages over doing it wherever any future returning failure dictates.

To be clear, changing the alternator isn't a guaranteed fix, but it should eliminate some variables.

:cheers: vic
What connectors are prone to failing that could have these symptoms?

KulAdventures.net
 

Nautamaran

2004 140” HRC 2500 (Crewed)
No idea... I had a similar gremlin in a Mazda hatch back years ago. Battery went flat, dash lights faded to black, then suddenly everything came back to life. Drove it another six months with no issues before it was rear ended by a drunk driver while parked, so I can’t say how long it would have lasted on its second wind. Looking back I’d check the regulator current.

The alternator excitation is controlled by the instrument cluster, so perhaps pop the dash hump and trace it for faults.
Otherwise, be sure the new alternator has a clutch or you’ll send pulses through the belt and quickly wear out your tensioner.

-dave
 

Aqua Puttana

Poly - Thread Finder
What connectors are prone to failing that could have these symptoms?

KulAdventures.net
:idunno:

The symptoms that you describe are not known to me. As happens often, I have no "this will work" suggestions. I'm suggesting that you improve your odds.

Ground connections are a frequent culprit. There are both lug connections and OEM MB connectors on the alternator electrics, either of which can develop problems.

The point is more that exchanging the alternator at a relatively convenient time and eliminating the alternator as a suspect has value over continued doubt and possibly interrupting your trip at some random time.

vic
 
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Midwestdrifter

Engineer In Residence
I would check the ground strap at the engine, and the small wire on the back of the alt. The clutch can sometimes start sticking open, which may have caused your no charge event. If you drop the belt, you can give it a spin by hand.
 

autostaretx

Erratic Member
" whiring type of noise" ... so it could be the over-running clutch on the alternator.

Buying a new one includes a new clutch, so that covers you both ways (electrical and mechanical)

--dick
 

alexk243

KulAdventure
So I went ahead and replaced the alternator in the parking lot of advanced Auto near Olympia Washington. The old one was definitely shot. Hard to turn and did not appear that the clutch (decoupler) was functional.

Went with their rebuilt 150a one... Not my first choice, but it had to be done on the road. Should be good to go now. I'll report back when I make some distance on it.

KulAdventures.net
 

Midwestdrifter

Engineer In Residence
Rebuild alternators from AutoZone etc. have a poor reputation. Not that you had a choice.
I would pay attention to it and possibly expect to replace it sometime in the next 10 or 20,000 miles.
 
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alexk243

KulAdventure
Rebuild alternators from AutoZone etc. have a poor reputation. Not that you had a choice.
I would pay attention to it and possibly expect to replace it sometime in the next 10 or 20,000 miles.
Yeah, I figured as much. Will probably order another Bosch OEM one eventually. Keeping an eye on it for now. At least it got me on the road.

KulAdventures.net
 
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autostaretx

Erratic Member
Given the pant legs, it's a good thing you did the work in front of a cleaner's?

good luck
--dick
 

Aqua Puttana

Poly - Thread Finder
The auto supply house alternators wouldn't be my first choice, but the units don't always automatically fail.

Yeah, I figured as much. Will probably order another Bosch OEM one eventually.

...
If no core charge, keep the removed unit and have it assessed/rebuilt by a local shop when convenient. For most use 90 vs 150 amps isn't a huge or necessary improvement for proper service.

Good to hear you're back in service.

:cheers: vic
 

Aqua Puttana

Poly - Thread Finder
That definitely not OEM Bosch.
Cincinnati OH?

https://jnelectric.com/startpage.asp?tab=his

They list Bosch and Valeo.
***
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vic
 
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kansascitysprinters

t1n everything
Rebuild alternators from AutoZone etc. have a poor reputation. Not that you had a choice.
I would pay attention to it and possibly expect to replace it sometime in the next 10 or 20,000 miles.
I would second this. I ended up replacing mine rebuild as well.
 

Pasieka

Member
This is how I test if it's the bat or alternator in a pinch... loosen negative terminal, starts car, while running remove negative post, if car dies = regulator, if car runs better = batery

Sent from my SM-N950U using Tapatalk
 

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