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Home » Public Forums » GMCnet » ALTERNATOR NOT CHARGING BATTERY
ALTERNATOR NOT CHARGING BATTERY [message #108154] Fri, 10 December 2010 22:38 Go to next message
sonny is currently offline  sonny   United States
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Two mechanics pouring over manuals and schematics can't figure it out. Why does the alternator not charge the battery? Any guesses or similar experiences out there? Thanks for your help!

Sonny Miles
Re: ALTERNATOR NOT CHARGING BATTERY [message #108157 is a reply to message #108154] Fri, 10 December 2010 22:45 Go to previous messageGo to next message
GeorgeRud is currently offline  GeorgeRud   United States
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The alternator is a standard GM alternator, but I wonder if your battery isolator went bad. You can check to see if you're getting voltage at the center terminal of the isolator to see if the alternator is putting out voltage. If it is, then it must be the isolator.

George Rudawsky
Chicago, IL
75 Palm Beach
Re: ALTERNATOR NOT CHARGING BATTERY [message #108158 is a reply to message #108154] Fri, 10 December 2010 22:52 Go to previous messageGo to next message
MR.ERF is currently offline  MR.ERF   United States
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There is a lot not shown here

is the alternator good?
is the battery good

what has been done?
do you have an apc cable?
gene
Re: ALTERNATOR NOT CHARGING BATTERY [message #108159 is a reply to message #108158] Fri, 10 December 2010 23:17 Go to previous messageGo to next message
WD0AFQ is currently offline  WD0AFQ   United States
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What George said. If alternator is working properly then you are not getting that charge to the battery. You should have voltage to that stud on the isolator. Jump it over to battery and it will be charging the battery. Bad connection or bad isolator. I had a bad isolator and replaced it with a combiner. Your 2 mechanics should have been able to find this. Might want to look for a new one.
Dan


3 In Stainless Exhaust Headers One Ton All Discs/Reaction Arm 355 FD/Quad Bag/Alum Radiator Manny Tran/New eng. Holley EFI/10 Tire Air Monitoring System Solarized Coach/Upgraded Windows Satelite TV/On Demand Hot Water/3Way Refer
Re: ALTERNATOR NOT CHARGING BATTERY [message #108163 is a reply to message #108154] Sat, 11 December 2010 02:25 Go to previous messageGo to next message
Ken Burton is currently offline  Ken Burton   United States
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Not enough information.

What is the voltage on the output of the alternator? You can read it on the center post of hte isolator.

What is the voltage across the engine battery when the alternator is running? Read is right across the battery.

What is the voltage across the house battery when engine battery is running. Read it right across the battery.

My wild ass guess is you do not have the start lead going to the alternator energized so the alternator never comes to life.

Answer the above 3 questions and we can give you more information.

It sounds like your mechanics are parts swappers and not real diagnosticians.



Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
Re: ALTERNATOR NOT CHARGING BATTERY [message #108173 is a reply to message #108154] Sat, 11 December 2010 08:27 Go to previous messageGo to next message
mike miller   United States
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Location: Hillsboro, Oregon
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Senior Member
sonny wrote on Fri, 10 December 2010 20:38

Two mechanics pouring over manuals and schematics can't figure it out. Why does the alternator not charge the battery? Any guesses or similar experiences out there? Thanks for your help!


I noticed this is Sonny's first and only message to the board. (welcome aboard!!) I did wonder if he was even talking about a TZE type motorhome or some other kind of GMC....

So I checked his profile: "Living as a personal assistant to an aging inventor about to travel the country in the Old Eleganza II." and has a location of "Swartz Creek, Michigan."

So Sonny seems to be "one of us." (I know we'd normally help anyway...)

Sonny,

As others have mentioned, we'll need more information. Our motorhomes came with a two battery system that, while quite simple, can confuse a normal auto mechanic. Also there has been over 30 years for owners and "mechanics" to "fix" it "good." (ie: there may have been changes.)

If I where you, first thing I would do would check the "black list" for someone local. Sometimes an eye that is "familar" with the system, will spot obvious issues that would take forever "passing notes" back and forth.

Other things to think about, what battery are you checking, (house / engine or both) How old is it? (Will it hold a charge if charged with a battery charger and disconnected from the coach?) Are the cables clean and tight? Is the alternator putting out any juice? Check at the center post on the issolater. (As others have stated.)

Let us know... we'll help if we can.


Mike Miller -- Hillsboro, OR -- on the Black list
(#2)`78 23' Birchaven Rear Bath -- (#3)`77 23' Birchaven Side Bath
More Sidekicks than GMC's and a late model Malibu called 'Boo' http://m000035.blogspot.com
Re: ALTERNATOR NOT CHARGING BATTERY [message #108175 is a reply to message #108163] Sat, 11 December 2010 08:34 Go to previous messageGo to next message
sonny is currently offline  sonny   United States
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Junior Member
Thanks, Ken.

I'm off to the garage right now. The mechanics working on this thing have been trading notes and swapping alternators for five days. Maybe this will give them a direction to move in.'

Happy to now the forum works so well!


Sonny Miles
Re: ALTERNATOR NOT CHARGING BATTERY [message #108176 is a reply to message #108173] Sat, 11 December 2010 08:37 Go to previous messageGo to next message
sonny is currently offline  sonny   United States
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Thanks, Mike.

No doubt about it, I got a lot to learn about this motorhome. It looks like the Boss wants to ride down to Belize over the next few months so I'm gathering all the information I can on the unit and reading a lot.

Glad to be part of the forum - it let's me feel safe!


Sonny Miles
Re: [GMCnet] ALTERNATOR NOT CHARGING BATTERY [message #108179 is a reply to message #108173] Sat, 11 December 2010 09:00 Go to previous messageGo to next message
mlincoln is currently offline  mlincoln   United States
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Location: Salt Lake City
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I saw a listing on Craigslist from Sonny yesterday; he was looking for a maintenance manual to solve his charging problem. I replied to him over CL and suggested he get Tom Lins DVD and join the list, which he didn't know about. Let's all welcome him!

Also, Sonny, George Enochs at Mint City Motors in St Johns works on these (he owns one)

Mike Lincoln
1978 CK Royale
Ann Arbor MI
Sent from my iPhone

On Dec 11, 2010, at 9:27 AM, Mike Miller <m000035@gmail.com> wrote:

>
>
> sonny wrote on Fri, 10 December 2010 20:38
>> Two mechanics pouring over manuals and schematics can't figure it out. Why does the alternator not charge the battery? Any guesses or similar experiences out there? Thanks for your help!
>
>
> I noticed this is Sonny's first and only message to the board. (welcome aboard!!) I did wonder if he was even talking about a TZE type motorhome or some other kind of GMC....
>
> So I checked his profile: "Living as a personal assistant to an aging inventor about to travel the country in the Old Eleganza II." and has a location of "Swartz Creek, Michigan."
>
> So Sonny seems to be "one of us." (I know we'd normally help anyway...)
>
> Sonny,
>
> As others have mentioned, we'll need more information. Our motorhomes came with a two battery system that, while quite simple, can confuse a normal auto mechanic. Also there has been over 30 years for owners and "mechanics" to "fix" it "good." (ie: there may have been changes.)
>
> If I where you, first thing I would do would check the "black list" for someone local. Sometimes an eye that is "familar" with the system, will spot obvious issues that would take forever "passing notes" back and forth.
>
> Other things to think about, what battery are you checking, (house / engine or both) How old is it? (Will it hold a charge if charged with a battery charger and disconnected from the coach?) Are the cables clean and tight? Is the alternator putting out any juice? Check at the center post on the issolater. (As others have stated.)
>
> Let us know... we'll help if we can.
> --
> Mike Miller
>
> #01 - `73 26' X Painted D. "The Spare"
> #02 - `78 23' Birchaven Rear Bath "The User"
> #03 - `77 23' Birchaven Side Bath "The Keeper"
> Hillsboro, OR
> _______________________________________________
> GMCnet mailing list
> List Information and Subscription Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
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Mike
Re: [GMCnet] ALTERNATOR NOT CHARGING BATTERY [message #108185 is a reply to message #108176] Sat, 11 December 2010 09:15 Go to previous messageGo to next message
Ken Henderson is currently offline  Ken Henderson   United States
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Registered: March 2004
Location: Americus, GA
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If "It looks like the Boss wants to ride down to Belize over the next few
months." means what it sounds like it means -- in the GMC, you need to have
SERIOUS talk with "the Boss".

If you can't even get a trivially simple problem like an alternator not
charging repaired by two mechanics here in the US, what in the world do you
think's going to happen once you cross the southern border? Granted, the
mechanics in less developed areas may be more ingenious than our "parts
swapping" spoiled ones, but the fact is that they won't know anything about
the peculiar systems of the GMC. It's also unlikely that you'll have ready
access to the GMCNet or Black List for assistance. And UPS won't be able to
get parts to you as quickly as in the US & Canada. You ARE aware, I
presume, that there are some relatively routine maintenance tasks (front
wheel bearing R&R, engine or transmission R&R, etc.) that require
specialized tools which will not be available at ANY location south of the
border.

There's not much on my GMC I can't fix after owning it for 12 years and
rebuilding 'most everything on it, but I wouldn't even THINK of attempting
such a trip in it. Not even if the highway system was up to US standards
and there was no criminal activity to consider -- the GMCNet may make you
"feel safe", but you won't be.

Sounds like a fool's errand to me.

JMHO,

Ken H.


On Sat, Dec 11, 2010 at 9:37 AM, Roger Christian <samaritan1945@gmail.com>wrote:

> ...No doubt about it, I got a lot to learn about this motorhome. It looks
> like the Boss wants to ride down to Belize over the next few months so I'm
> gathering all the information I can on the unit and reading a lot.
>
>
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Ken Henderson
Americus, GA
www.gmcwipersetc.com
Large Wiring Diagrams
76 X-Birchaven
76 X-Palm Beach
Re: [GMCnet] ALTERNATOR NOT CHARGING BATTERY [message #108186 is a reply to message #108176] Sat, 11 December 2010 09:20 Go to previous messageGo to next message
Mr ERFisher is currently offline  Mr ERFisher   United States
Messages: 7117
Registered: August 2005
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Senior Member
has been done before, (I wish I had pictures) the GMC even had dual tires
on the front

a few years ago, there was a guy on here looking for a pardner coach to go
with him down that side of the coast,
not sure what ever happened to him.

maybe some of our historians will have some info
gene


>
> Thanks, Mike.
>
> No doubt about it, I got a lot to learn about this motorhome. It looks
> like the Boss wants to ride down to Belize over the next few months so I'm
> gathering all the information I can on the unit and reading a lot.
>
> Glad to be part of the forum - it let's me feel safe!
> --
> Sonny Miles
> _______________________________________________
> GMCnet mailing list
> List Information and Subscription Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>



--
Gene Fisher -- 74-23,77PB/ore/ca
“Give a man a fish; you have fed him for today --- give him a URL and
-------
http://gmcmotorhome.info/
Alternator Protection Cable
http://gmcmotorhome.info/APC.html
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Re: [GMCnet] ALTERNATOR NOT CHARGING BATTERY [message #108187 is a reply to message #108185] Sat, 11 December 2010 09:33 Go to previous messageGo to next message
Charles is currently offline  Charles   United States
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Registered: January 2004
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Ken said "Sounds like a fool's errand to me."
Just this morning at a local donut shop two Mexicans
from the Mexico city area said they are afraid to go
back home. Drug cartel are just too rampant. Well
off Mexicans and Americans are no longer safe in
Mexico. I'm with Ken, Roger should reconsider going
south.
Charles
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Charles Wersal
Duncanville, Texas
26 foot 1975 Glenbrook
Pandora's Box

Re: ALTERNATOR NOT CHARGING BATTERY [message #108188 is a reply to message #108154] Sat, 11 December 2010 09:54 Go to previous messageGo to next message
Craig Lechowicz is currently offline  Craig Lechowicz   United States
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Location: Waterford, MI
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Senior Member
sonny wrote on Fri, 10 December 2010 23:38

Two mechanics pouring over manuals and schematics can't figure it out. Why does the alternator not charge the battery? Any guesses or similar experiences out there? Thanks for your help!



Sonny,
I'm about an hour away in Waterford. If your guys aren't making any progress, I could probably zip up and take a look at it. craig dot lechowicz at sbcglobal dot net (remove spaces and dot's) or 248-252- seven one six six.


Craig Lechowicz
'77 Kingsley, Waterford, MI
Re: ALTERNATOR NOT CHARGING BATTERY [message #108192 is a reply to message #108176] Sat, 11 December 2010 10:28 Go to previous messageGo to next message
Matt Colie is currently offline  Matt Colie   United States
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Senior Member
sonny wrote on Sat, 11 December 2010 09:37

Thanks, Mike.

No doubt about it, I got a lot to learn about this motorhome. It looks like the Boss wants to ride down to Belize over the next few months so I'm gathering all the information I can on the unit and reading a lot.

Glad to be part of the forum - it let's me feel safe!

Sonny,

In my world, extended foreign cruises are known as going to exotic locations to make (expensive) repairs.

RV's are no different in that respect.

But........
The drug cartels have killed 7000 Mexicans just in the frontieria (border states) in the just this last year. The Mexican government does not publish national statistics. Foreigners and wealthy are prime targets for kidnapping for ransom anyplace that does not have police and military presents.

PO+1 of my coach used to take it to Mexico before the current wars. Every external opening locks and the windows all double lock. He also had a very good set of spares and the complete paper manual and a parts book.

If there were no violence and there was good highway, this would still be a very serious undertaking. As it is, it would be fool hearty at best - maybe suicidal.

As to your charging problem.
As others have said, you have parts changers (called installers in the trade) not real mechanics. All it takes is a voltmeter and a screwdriver to do a complete diagnosis of a period GM alternator and if that was done, they probably would not have taken off the original alternator.

Does the APU (genset) work? You can use it to power the engine systems while you drive to coach to a competent mechanic.

If you charge the starting battery and do nothing else, you should be able to run for 2~3 hours in daylight to get some where that has the talent you need. If you think St. Johns is too far, there is always Cinnabar in Sandusky (MI). That is, if Craig can't straighten it out.

Good Luck

Matt


Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Near DTW - Twixt A2 and Detroit
Re: [GMCnet] ALTERNATOR NOT CHARGING BATTERY [message #108196 is a reply to message #108154] Sat, 11 December 2010 11:36 Go to previous messageGo to next message
James Hupy is currently offline  James Hupy   United States
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Registered: May 2010
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Senior Member
Two uninformed mechanics does not equal one technician that is up to speed
on a GMC, but a battery isolator is a generic device found on many
Motorhomes. If those two guys can't trouble shoot one, ask if their names
are Darrell & Darrell. Be prepared to leave in a hurry. Ha Ha.
Jim Hupy
Salem, Or
78 Royale 403

On Fri, Dec 10, 2010 at 8:38 PM, Roger Christian <samaritan1945@gmail.com>wrote:

>
>
> Two mechanics pouring over manuals and schematics can't figure it out. Why
> does the alternator not charge the battery? Any guesses or similar
> experiences out there? Thanks for your help!
> --
> Sonny Miles
> _______________________________________________
> GMCnet mailing list
> List Information and Subscription Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>
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Re: [GMCnet] ALTERNATOR NOT CHARGING BATTERY [message #108211 is a reply to message #108154] Sat, 11 December 2010 14:50 Go to previous messageGo to next message
jw mills is currently offline  jw mills   United States
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Registered: September 2006
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Senior Member
Get a $10 volt meter
1 Is there 13 - 14 volts at the big stud on the alternator?
No - take alternator to Auto Zone to test alternator

2 Is the same voltage at the center stud on the isolator?
No - broken wire between alternator and isolator

3 Is the same voltage at the side studs on the isolator?
No - bad Isolator (one side stud is engine battery, the other is
coach)

4 Is the same voltage at the POS terminal of battery
No - broken wire between battery and isolator OR
bad ground strap on battery

After this it gets harder.

--
Jim Mills
Greeley, CO
1973 CanyonLands 260 TZE-063V100731(under renovation)
1973 Glacier 230 TZE-033V101993


On Fri, 2010-12-10 at 22:38 -0600, Roger Christian wrote:

>
> Two mechanics pouring over manuals and schematics can't figure it out. Why does the alternator not charge the battery? Any guesses or similar experiences out there? Thanks for your help!
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Re: [GMCnet] ALTERNATOR NOT CHARGING BATTERY [message #108215 is a reply to message #108211] Sat, 11 December 2010 15:44 Go to previous messageGo to next message
emerystora is currently offline  emerystora   United States
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Registered: January 2004
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Senior Member

On Dec 11, 2010, at 1:51 PM, mills wrote:

> Get a $10 volt meter
> 1 Is there 13 - 14 volts at the big stud on the alternator?
> No - take alternator to Auto Zone to test alternator
>
> 2 Is the same voltage at the center stud on the isolator?
> No - broken wire between alternator and isolator
>
> 3 Is the same voltage at the side studs on the isolator?
> No - bad Isolator (one side stud is engine battery, the other is
> coach)
>
> 4 Is the same voltage at the POS terminal of battery
> No - broken wire between battery and isolator OR
> bad ground strap on battery
>
> After this it gets harder.
>
> --
> Jim Mills
> Greeley, CO

Good advice. In number 3, though, they should expect approx .7 volts less than number 2 because of the small voltage drop of the diode in the isolator.

Emery Stora
77 Kingsley
Santa Fe, NM


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Re: [GMCnet] ALTERNATOR NOT CHARGING BATTERY [message #108223 is a reply to message #108211] Sat, 11 December 2010 17:14 Go to previous messageGo to next message
gmchunter is currently offline  gmchunter   United States
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Registered: March 2008
Location: ORANGE, CA
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Senior Member
That would be great info. If I knew how to use a voltmeter.

Michael
Re: [GMCnet] ALTERNATOR NOT CHARGING BATTERY [message #108225 is a reply to message #108186] Sat, 11 December 2010 17:11 Go to previous messageGo to next message
USAussie is currently offline  USAussie   United States
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Location: Sydney, Australia
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Senior Member
Gene,

IIRC there was a guy at the Santa Rosa Convention promoting the idea of a
"group drive" from the USA down to the tip of South America.

Now that guy was really optimistic, eh?

Regards,
Rob M.
USAussie - Downunder

-----Original Message-----
From: gmclist-bounces@temp.gmcnet.org
[mailto:gmclist-bounces@temp.gmcnet.org] On Behalf Of Mr.erf ERFisher
Sent: Sunday, December 12, 2010 2:20 AM
To: gmclist@temp.gmcnet.org
Subject: Re: [GMCnet] ALTERNATOR NOT CHARGING BATTERY

has been done before, (I wish I had pictures) the GMC even had dual tires
on the front

a few years ago, there was a guy on here looking for a pardner coach to go
with him down that side of the coast,
not sure what ever happened to him.

maybe some of our historians will have some info
gene


>
> Thanks, Mike.
>
> No doubt about it, I got a lot to learn about this motorhome. It looks
> like the Boss wants to ride down to Belize over the next few months so I'm
> gathering all the information I can on the unit and reading a lot.
>
> Glad to be part of the forum - it let's me feel safe!
> --
> Sonny Miles
> _______________________________________________
> GMCnet mailing list
> List Information and Subscription Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>



--
Gene Fisher -- 74-23,77PB/ore/ca
"Give a man a fish; you have fed him for today --- give him a URL and
-------
http://gmcmotorhome.info/
Alternator Protection Cable
http://gmcmotorhome.info/APC.html
_______________________________________________
GMCnet mailing list
List Information and Subscription Options:
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_______________________________________________
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Regards, Rob M. (USAussie) The Pedantic Mechanic Sydney, Australia '75 Avion - AUS - The Blue Streak TZE365V100428 '75 Avion - USA - Double Trouble TZE365V100426
Re: [GMCnet] ALTERNATOR NOT CHARGING BATTERY [message #108226 is a reply to message #108223] Sat, 11 December 2010 17:16 Go to previous messageGo to previous message
Ken Burton is currently offline  Ken Burton   United States
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gmchunter wrote on Sat, 11 December 2010 17:14

That would be great info. If I knew how to use a voltmeter.

Michael

You get the meter and we will teach you in a few minutes.



Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
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