The coach has been sitting since last Oct 2017. My wife and I were going to head south last February but she got sick, she passed away in June. I haven't decided whether to keep the motorhome or not but Thursday I took it out for an overnight just to see how it would be alone. The charging system is not working and the check engine light came on seemingly when the battery voltage got too low. When I turned off the lights and and AC the cel went out once the batteries recovered some on their own. I have looked at the alternator and all connections seem fine. I tapped on it slightly to see if I could free up any potentially stuck brushes. Battery connections are good, clean and tight. I wanted to try to figure out what I would need for a replacement alternator just in case but I do not see any tag or numbers on it anywhere. Any help or suggestions would be appreciated. Likely I'll need to take it to the garage.2005 Holiday Rambler Ambassador 36PDD

Hey Bassman, I can't help you with the rest of your life, that prospect scares me and I can only wish you all the best. As to the charging circuits. It sounds like you have several problems with the coach. I would suggest that you try to charge what you can with shore power and then either you or another do a full diagnosis. You may just have a bank gone so flat that nothing can work. Good Luck Matt

Can you get the engine started? Have AAA come give you a jump?If you didn't disconnect the grounds while the rig sat, yes, the batteries will be dead or nearly dead after all that time. AFA the alternator goes, service the batteries (add water, clean the terminals), get it started and after running the engine 5-10 minutes, measure the voltage at the batteries. It should be in the 13 Volt range. If it's way low, like 10-11 volts, then you might have a bad alternator.More than likely, it's just dead batteries.

As suggested, use 120 VAC and either your onboard charger or if deeply discharged, a stand along "not-smart" charger.Only have battery fully charged should you start trouble shooting the 12 VDC system.

Yes It starts and I drove it about 3 hours but it didn't charge that whole time. The batteries were never dead, I kept it plugged in all the time.

wtmtnhiker wrote:Yes It starts and I drove it about 3 hours but it didn't charge that whole time. The batteries were never dead, I kept it plugged in all the time.Could be the alternator but it's odd that it would fail while just sitting. I'd wonder if the feed line from the IGN switch hadn't corroded 'open circuit' and you're not getting any field voltage? (Yes, many newer RVs have alternators that self generate their own field voltage, but a 2005 rig might use field voltage supplied from the cockpit).So, yeah, you might need to go to the shop for diagnosis. The alternators on truck chassis' do tend to be robust though, so I'd look for something like corrosion or broken or rodent chewed through wire associated with the alternator first.

Charging system | Good Sam Community

Roadpilot
Explorer
Sep 01, 2018
I wonder if you could be more explicit what happened when. You mentioned you took the coach out for 3 hours and the check engine came on. I assume that was when you were driving but you also said you shut off some lights and the AC (air conditioner?) and the light went out.

Or did you drive somewhere and spend the night then in the morning start the coach and you had a check engine light? Were you plug in over night?

Anyway, if you could tell us the exact sequence of events it would help.

Sorry for your loss. We are in the NH Seacoast by the way.
wolfe10
Explorer
Sep 01, 2018
Yes, in an emergency you can run the generator which powers your converter, charger or inverter/charger to charge (at least) the house battery bank.

On most coaches, it will NOT charge the chassis battery. So, to drive, you will need to either use your boost/combine switch or physically connect the battery banks-- you have to have the chassis battery at above 12 VDC while driving, as it powers the engine and transmission computers!
tropical36
Explorer
Sep 01, 2018
wtmtnhiker wrote:
The coach has been sitting since last Oct 2017. My wife and I were going to head south last February but she got sick, she passed away in June.
I haven't decided whether to keep the motorhome or not but Thursday I took it out for an overnight just to see how it would be alone. The charging system is not working and the check engine light came on seemingly when the battery voltage got too low. When I turned off the lights and and AC the cel went out once the batteries recovered some on their own.
I have looked at the alternator and all connections seem fine. I tapped on it slightly to see if I could free up any potentially stuck brushes. Battery connections are good, clean and tight.
I wanted to try to figure out what I would need for a replacement alternator just in case but I do not see any tag or numbers on it anywhere. Any help or suggestions would be appreciated. Likely I'll need to take it to the garage.

2005 Holiday Rambler Ambassador 36PDD

You should be able to run the generator and for getting enough of a charge for driving it home.
Once there or even with where you're camped, the best thing is to remove the alternator, once verified bad and take it to NAPA or other for a match and also with possible having the originally pulley changed out.
enblethen
Nomad
Sep 01, 2018
New Hampshire!
First guess is the battery froze sitting since Oct.
Battery shorted.
Remove battery and have it checked. Look for bulging in battery case.
Sorry for your loss!
wolfe10
Explorer
Sep 01, 2018
wtmtnhiker wrote:
Yes It starts and I drove it about 3 hours but it didn't charge that whole time. The batteries were never dead, I kept it plugged in all the time.

Please tell us voltage before starting and while driving.

"Didn't charge that whole time" is a little vague.

And, have you checked battery water level and connections for cleanliness/tightness?
Jim
Explorer
Sep 01, 2018
wtmtnhiker wrote:
Yes It starts and I drove it about 3 hours but it didn't charge that whole time. The batteries were never dead, I kept it plugged in all the time.

Could be the alternator but it's odd that it would fail while just sitting. I'd wonder if the feed line from the IGN switch hadn't corroded 'open circuit' and you're not getting any field voltage? (Yes, many newer RVs have alternators that self generate their own field voltage, but a 2005 rig might use field voltage supplied from the cockpit).

So, yeah, you might need to go to the shop for diagnosis. The alternators on truck chassis' do tend to be robust though, so I'd look for something like corrosion or broken or rodent chewed through wire associated with the alternator first.
wtmtnhiker
Explorer
Sep 01, 2018
Yes It starts and I drove it about 3 hours but it didn't charge that whole time. The batteries were never dead, I kept it plugged in all the time.
wolfe10
Explorer
Sep 01, 2018
As suggested, use 120 VAC and either your onboard charger or if deeply discharged, a stand along "not-smart" charger.

Only have battery fully charged should you start trouble shooting the 12 VDC system.
Jim
Explorer
Sep 01, 2018
Can you get the engine started? Have AAA come give you a jump?

If you didn't disconnect the grounds while the rig sat, yes, the batteries will be dead or nearly dead after all that time.

AFA the alternator goes, service the batteries (add water, clean the terminals), get it started and after running the engine 5-10 minutes, measure the voltage at the batteries. It should be in the 13 Volt range. If it's way low, like 10-11 volts, then you might have a bad alternator.

More than likely, it's just dead batteries.
Matt_Colie
Explorer II
Sep 01, 2018
Hey Bassman,

I can't help you with the rest of your life, that prospect scares me and I can only wish you all the best.

As to the charging circuits. It sounds like you have several problems with the coach. I would suggest that you try to charge what you can with shore power and then either you or another do a full diagnosis. You may just have a bank gone so flat that nothing can work.

Good Luck

Matt

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