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Alternator Woes

My voltmeter showed variations from normal (13. + to pegged) as I was on the road.

It settled down to 14+ but seemed temperature dependent. (as I slowed down the voltage went up.
I managed to get to a truck repair facility who was willing to take a look.
The diagnosis was the alternator regulator.

Ordered a new Leece-Neville alternator A0012800LC.

After installation and  attempts to wire the alternator correctly we wound up with the techs best efforts -  It looks like the alternator charges the chassis batteries but the ignition circuit is still on. By that I mean that several systems think that the ignition is on.  Like the oil pressure warning is on, the bell rings, the level system is on, etc.tsome how

I.e the ignition system is appears ON to the coach

I have taken the energizing wires off the ignition solenoid  to no avail.

There is an alternator shop here in Madison, WI I will query tomorrow.
 

In the meantime I have taped the annunciator  and will put up with the lights from the dash.

An solutions welcome
Elliott & Mary Bray
ex. 1996 36' U295 - Build 4879
ex. 2018 Coachmen Leprechaun 319MB
 

Re: Alternator Woes

Reply #1
Did you keep the old one?Compare the 2 to see how the new one is different and go from there.I still believe in having the old ones
rebuilt over a new one,mine lasted 20 years and yours lasted 21.
96 U270 BUILD 4810
85 380SL
Drummonds TN.

Re: Alternator Woes

Reply #2
If it is like our alternator, the old one was rewired internally for a DUVAC mode. I would check and see if that is what is going on. Wolfe 10 sure helped us when we were broken down in the middle of nowhere. You should be able to find that thread under tech topics.

Len
Len and Deb Speiser
1999 U270 36'
2017 Jeep Wrangler Unlimited
You're either on the bus, or you're off the bus!--Ken Kesey
If you're lucky enough to live in a bus, you're lucky enough!

Re: Alternator Woes

Reply #3
Elliott,

Looks like the alternator isn't wired up for a DUVAC system.  Here is a link to how to change it over.
file:///C:/Users/owner/Downloads/LN%20alternator/Technical%20Services.htm
Most any old time alternator shop can follow these instructions if you can't DIY.

Pamela & Mike
Pamela & Mike 97 U 320

"It's not what happens to you, but how you react to it that matters."

Re: Alternator Woes

Reply #4
Your alternator ignition wire is miswired and back feeding 12v into your dash. Have the alternator shop check your wiring. Most techs don't understand duvac alternators and isolators.
Peter and Tammy Fleming
1991 U300 GV 40 - Sold, owned for 4 years
Downsized to Roadtrek Popular 210 class B

Re: Alternator Woes

Reply #5
If you have your coach fuse chart, there should be a fuse for the alternator ignition wire, on my coach it was labeled "ALT EXC 10" meaning it is a 10 amp fuse. If you pull that fuse it should shut off the stuff that is still getting power with the coach off. This will prevent additional drain on your batteries overnight, until you can get some help.
Peter and Tammy Fleming
1991 U300 GV 40 - Sold, owned for 4 years
Downsized to Roadtrek Popular 210 class B

Re: Alternator Woes

Reply #6
Peter,
I'm looking fhru my docs.
Where would the fuse box be located?
The 12v stuff under the bed is just lights and such

thanks

Addendum....

FOUND IT!!
 Or at least the busbar  location.
In the dash electrical panel  Position 35
unbolted the common wire
Stopped the bleeding for now

Again, Thanks for the lead.
Elliott & Mary Bray
ex. 1996 36' U295 - Build 4879
ex. 2018 Coachmen Leprechaun 319MB
 

Re: Alternator Woes

Reply #7
Elliot,
Does the replacement alternator exactly match your old one?  Can't you buy just the voltage regulator?  It is easy to replace on our L-N alternators.  That would eliminate your back feed problem.
Regards,
Brett

'99 42' Foretravel Xtreme
'14 Brown Motorsports Stacker
'05 Chevy SSR
'02 BMW R1150R

Re: Alternator Woes

Reply #8
Pegged volts  are not good.
In a coach like a Fortravel high voltage should disconnect the alternator, give you a warning light, let you start that generator and engage the boost switch. Go down the road and enjoy your day and have nothing to worry about.  Deal with it in the morning!
Automation is great!
John Duld
1995 U320C SE 40'

Re: Alternator Woes

Reply #9
Currently at park in Oregon,no charging voltage,ran coach all day but did'nt run ac,no voltage out of alternator,will look for the
fuse in morning.All batteries charging while on ac power,seperate charger on start batteries,cannot run gen(hole in radiator).
Worse come to worse will limp home like this.
96 U270 BUILD 4810
85 380SL
Drummonds TN.

Re: Alternator Woes

Reply #10
To finish off my part of this tale.

When last we visited, the truck place (Truck Country in Marinette, WI) had ordered and installed a new Leece-Neville alternator.
Same part number as called for on the plate.
EXCEPT the old alternator also had metal stickers that said the alternatoe was wired for DUVAC service.
These guys had no clue and while I knew theoretically that what I needed, I wasn't quick enough to add anything to the conversation.
I was just glad I had found someone to work on it and could have the part tomorrow.

Anyway , installed (after interesting time getting 8 grove pulley off) . Wouldn't quite work right but there was what looked like a good alternator shop in Madison, where we had a long stay scheduled.

I'll shorten the tale.
As mentioned above, I found the post in the wiring panel in front of the passenger seat (thanks again Peter) and disconnected the excite wire to cut power to the ignition switch

Come Monday morning I get a call at 8:00 from Mike Hardy at
Finicki Auto Electric Starter Rebuilding Madison WI, Alternator Rebuilding Madison WI.

I'll shorten even more.
I drove the coach over to his shop.
Parked beside in the alley next to the side door where I was able to ran a 15 amp line.
That afternoon he and his son took the new alternator out and into his shop We spent the night in the coach.
The next day the parts arrived to convert to a DUVAC and he installed, put the alternator back in, and the coach was ready to go by
 11:00am.

$160 parts and labor!!!!!

They were GREAT

Elliott & Mary Bray
ex. 1996 36' U295 - Build 4879
ex. 2018 Coachmen Leprechaun 319MB