No charge from Alternator

[Jkountz]

My chassis battery went dead, completely and wouldnt take a charge at all so I replaced it. I then discovered I wasnt getting a charge from the Alternator at all. Took it off and had it checked, turned out the alt was bad so I put a new one on. Now Im still not getting any charge. And to top it off theres some weird things going on as well. The gen wont crank either although the two coach batteries are showing charged. THat all worked fine before all this trouble started. The gen would crank and run just fine even when the chassis battery was shot. Never had a problem from that.  With the engine off if I hit the battery check button on the dash the chassis battery shows nothing, needle doesnt even move at all even though its fully charged from external charger. When I flip it over to check the coach batteries they show charged, needle goes right up to charge. Why would one show ok and not the other when they are both in fact charged up?? Wierd!!
Help!!

[Oz]

Have you gone through the charging system troubleshooting guides provided in the Member Area?

[Jkountz]

Ok so after some initial tests I have determined that the battery is fine (brand new) also it passed the continuity test from battery to alt both pos and neg. I am not getting anything from the alt to the battery however I ran out of daylight before I could run the test that determines if its the alt or the voltage reg. I will do that this evening. What still has me baffled is the fact that the on dash battery strength gauge will not read anything on the chassis battery but it will give me a reading for the coach batteries. Also I still have no power to the genset switch and the gen will still not crank. Could a faulty voltage reg prevent my genset from starting and would it also prevent the battery test gauge on the dash to read zero for the chassis battery but read ok for the coach battery? Weird. Im still thinking theres a wire broken somewhere thats causing all this. When I get home, its back to more testing!!

[Jkountz]

Update: Well the voltage regulator was shot so I put a new one on. Now it seems to be charging "a little" and by that I mean the gauge lays at 12v and stays there. I turn the headlights on and it drops a little bit but never does come back up to 12v. More like 11 or so. I still am not able to test the chassis battery with the motor off, the only time the gauge reads anything is when the motor is running. The coach batteries however will read whether its running or not.
I still dont have juice to the genset. Nothing, it wont crank at all. This just happened overnight with no explanation. It didnt start to die it just did.
I have been trying to go through the charging troubleshooting guide found here on this site but I dont have a proper AGR meter, Im using a digital meter I got years ago. It auto senses the current and reads V ohms and Amps. Can this serve my purposes ok or do I need an actual AGR meter?
Still looking for a broken wire or something somewhere since everything else has been replaced new.
So far, new Alt, battery, voltage reg and starter solenoid.
This is becoming very frustrating to say the least!!

[Jkountz]

Well Im still no where with my charging problem. I have run several tests and to be honest I dont really know what Im doing!! LOL Last night I started the motor, held the red probe of my voltmeter against the BAT terminal on the Alternator and the black one went to ground. I got a reading of 11.45. I also got this same reading at the two coach batteries when going to the positive and negative terminals with my meter. The gist is, my engine will start and run, my coach batteries are supplying power to the lights, water pump etc. However I cannot start my gen nor am I getting any charge to the batteries. I wish I knew more about what I was doing but all I can do is look for obvious broken or disconnected wires. I did find two relays, one looks to be the starting relay and the other I havent a clue, its not on my schematics. I hate this!! I want to take the MH on a camping trip this weekend since its the only one my wife and I have off together but Im afraid to run on battery power alone if Im not getting juice from the Alt. Which by the way was brand new. Maybe I got a bum one??

[Froggy1936]

You will read battery voltage at the alternator terminal But only with the engine shut off. With the engine running right after starting you should be reading 14.2 v  if it still reads 11 v the alternator is defective.  Frank

[ibdilbert01]

You'll also want to make sure its not your regulator, you can test this by checking the volts on the field plug on the alternator.   As we all know, the most unreliable parts can sometimes be new parts, so just because the regulator is new, don't rule it out as not being bad.   

Heres a quick lesson on alternators.   
http://www.misterfixit.com/alterntr.htm

[Jkountz]

Im starting to think I got a bad new alternator. Talk about irritating!! That thing couldnt be in a worse place to get to, a real bear to take off. That very well could be the problem with my charging but it doesnt explain why in the world my gen wont crank. Still cant figure that one out.

[DaveVA78Chieftain]

First, you have a John Deere chassis with a Ford power plant.  You have to use the chassis wiring diagram in the John Deere manual (pdf page 328).   Troubleshooting flow would be based on a Ford system.  Unfortunantly, the JD manual will not show coach side wiring (just chassis stuff).  To start, you need to just concentrate on the chassis charging system and forget the coach side stuff otherwise you are just confussing yourself.   Do not use the MOM switch set to the coach side for battery THe rig may start but, you masking the actual problem that way.  Set MOM to normal.  With MOM in normal, do you have voltage at the alternator BAT terminal?  Battery B+ goes from battery to starter relay to a fusible link to the alternator BAT terminal.  Path to ignition switch goes through some connectors and another fusible link to the switch.  There are tap offs for the light switch and the fuse box.  Your trying to discover where your losing the voltage path but you have to have the wiring diagrams first.

Dave

[Froggy1936]

Generator no crank --Separate problem that just happened at the same time ?  When you get another alternator have them test it before you buy it  Frank

[DaveVA78Chieftain]

I suspect a fusible link or bad connection being seen as multiple problems.  But you gotta use the right wiring diagram.

Dave

[Jkountz]

Hey Dave, I am using the John Deere Chassis Manual for my rig. Got it some time ago. My trouble is being ignorant of auto electrical systems in general!!

[DaveVA78Chieftain]

Thats a good start.  Not sure if you had found that page or not.  I have something I have to do and will be away from the keyboard for about 30 minutes.  I will try to pass on some hints then.  But just know, that if your not seeing at least 13.5V at the B+ terminal of the alternator  withthe engine running, then something is not right.   Will be back here shortly.

Dave

[DaveVA78Chieftain]

You need to start with cold checks.
1. Disconnect the coach batteries B+ terminal.  Simplyfy circuits so your not being mislead.  You will only see chassis battery voltage this way.
2.  Measure chassis battery voltage at battery to set a reference point.  All cold check readings should be within 0.5 VDC of that value.
3. Check voltage at alternator BAT terminal with ignition off.  Should be same as battery.
4. Check voltage at "A" terminal of regulator with ignition off.  Should be same as battery.
Note: A shorted noise suppresion capacitor at regulator can cause a fuseable link to open.
5. Check voltage at "B" terminal of ignition switch with ignition off.  Should be same as battery.
6.  Turn ignition switch ON (engine OFF).  Check voltage at "S" terminal of regulator.  Should be same as battery.
7. Turn ignition switch OFF.  Disconnect plug at regulator and lift lead from alternator FLD terminal.  Measure continuity of FLD lead from regulator to alternator.  Should be 0 ohms.
You can have an open in many places (fusible links (there are at least 2), connectors [C4, C6, C1]).  Corroded connections can also be a problem.

If that is OK, then you may have a defective new part

Regulator "A" lead is volatage monitor lead.
Regulator "F" lead is supply voltage to Alternator
Regulator "S" lead is power to Regulator.

Dave

[Jkountz]

Note: A shorted noise suppresion capacitor at regulator can cause a fuseable link to open.

Dave

Hey now we're getting somewhere I think, I saw an unconnected wire coming off the regulator. I tracked this down in the wiring diagram and it said it was a "radio capacitor". There is nothing connected to this wire at all, should there be?? It just looks like a little jumper wire hanging down. I thought this was just to keep noise out of the radio??

[Froggy1936]

That wire used to be the lead from a condenser that was used for radio suppression. Where did the condenser go ?? Where ever . You must remove this wire completely. If it grounds out this will cause problems.  Definatly check for open fuseable links  Frank

[Jkountz]

Well this just keeps getting better. While running through the checklist Dave posted for me the darn connector on the regulator decided it was time to die and broke on me while trying to unplug it. Man oh man, now I gotta go find one of those if I can and splice it in I guess. If and when I get that taken care of I'll post the results of the tests.

[DaveVA78Chieftain]

It's a Ford Truck based system.  Might have luck at a Ford Dealer.

Any of the Dorman products look like they would work?
http://www.dormanproducts.com/c-300-electrical-sockets-harnesses-4-wire.aspx
Dorman is the stuff on the red cards in the automotive help section of your typical auto supply.

Dave

[Jkountz]

You need to start with cold checks.
1. Disconnect the coach batteries B+ terminal.  Simplyfy circuits so your not being mislead.  You will only see chassis battery voltage this way.
2.  Measure chassis battery voltage at battery to set a reference point.  All cold check readings should be within 0.5 VDC of that value.

12.57 volts

3. Check voltage at alternator BAT terminal with ignition off.  Should be same as battery.

12.57 Volts

4. Check voltage at "A" terminal of regulator with ignition off.  Should be same as battery.

12.57 Volts

Note: A shorted noise suppresion capacitor at regulator can cause a fuseable link to open.

Took this wire off completely to eliminate the possiblity of a short

5. Check voltage at "B" terminal of ignition switch with ignition off.  Should be same as battery.

Where is this exactly? Not sure where to perform this test

6.  Turn ignition switch ON (engine OFF).  Check voltage at "S" terminal of regulator.  Should be same as battery.

11.75 Volts - Replaced regulator and got 12.57 Volts

7. Turn ignition switch OFF.  Disconnect plug at regulator and lift lead from alternator FLD terminal.  Measure continuity of FLD lead from regulator to alternator.  Should be 0 ohms.

O ohms

You can have an open in many places (fusible links (there are at least 2), connectors [C4, C6, C1]).  Corroded connections can also be a problem.

If that is OK, then you may have a defective new part

Regulator "A" lead is volatage monitor lead.
Regulator "F" lead is supply voltage to Alternator
Regulator "S" lead is power to Regulator.

Dave

So after all this here is where Im at:
Discovered one of the coach batteries was toast so I disconnected it and charged the other one to a full charge. This was done on Monday. I didnt get a chance to fiddle with it anymore until today and so I started the motor, and using the battery check switch on the dash I got 13.5 volts on the chassis battery within a min or two of starting. The once fully charged coach battery was at 9 volts!! If I switched the MOM switch to dual mode I then got 14 volts on the COACH battery and only 12 on the chassis. If I revved the motor the chassis battery eventually came up to 13.5 again. If I then switched out of dual mode I could literally watch the coach battery go back down to almost zero. The chassis battery went back to 12 for a while then back to 13.5. If I try to operate ANYTHING at all, lights, heater fan, wipers etc, my chassis battery drops to 11 and hangs there, does not go back up until the appliance is turned off. Then it will go back up.
This really has me baffled and quite PO'ed to be honest, Im just so tired of checking checking checking and not getting anywhere, I cleaned all my connections and they are in good condition. My generator will still not crank at all from either switch. Last fall when I parked it for the winter it ran fine. Not it does nothing.
AARRRRRRRRRGGGGGGGHHHHHHHHHHHHHH!!!!

So I dont know what to do at this point. Could all this be a faulty relay, I have two. One at the battery compartment and one under the hood connected to the regulator. How does one check these to see if THEY are bad??
Anyone?? Help!!

[Jkountz]

Ok folks the cleaning of ALL the terminals by by the battery box has yielded great results!! I am now getting a solid 14.3 volts on the B terminal of the alternator!! Also the chassis battery appears to be taking a charge now too.
Question: Using the "Batt Cond" switch on my dash to check the chassis battery it reads around 13+ volts. Now then if I turn on something like heater fan or headlights it drops to around 11.5 and stays there until I turn the appliance off then it will return to the 13+ volts in under a minute. Is this normal??
My in dash amp/volt gauge is still not working, dont know why yet. And of course my genset will still not crank at all but at least I appear to be charging now which is a huge plus!!
Thanks to everyone here who offered advice, I really appreciate it!!

[DaveVA78Chieftain]

There could be some component holding down the in dash circuit so,
Connect your voltmeter directly across your chassis battery and turn the lights, heater, etc. on and off and see the effect there.  If the charging voltage remains good there, then it's most corroded connections in the dash wiring.
Once you get all this working well, you can then start isolating the other problems.  You have to approach it a piece at a time or you will be comppletly confused.

I probably should not ask this (breaking my own logic rule), but can you start the genny at the genny itself (not the dash switch)?

Dave

[Jkountz]

Dave, Im not sure where in VA you are exactly but I need to get with you and buy you a cold beer!! You have been a tremendous help to me throughout this whole thing.
Having performed the check you mentioned in your last post I am happy to say I read 13.2 volts across the chassis battery with the motor off. I then had the wife start the motor and it went down to 11 something then right back up to 12.60 instantly. She turned the headlights, heater fan and wipers on and it didnt even so much as flicker hardly!! It remained right at 12.60-12.70. So can I assume I am charging properly and getting the right amount of charge from the alternator?? Seems to me that part is good and the gauge is just a piece of junk!! Please tell me this is the case!!

And to answer your question, not the genny wont start from either location. Wierd thing is, it did just fine last fall when I parked it. Whatever happened, just simply happened. Could this problem lie with the circuit breakers that are all wired to the isolator relay down by the battery compartment? I have four altogether that go to various things.

[ibdilbert01]

"13.2 volts across the chassis battery with the motor off."

A completely charged (in new condition) lead acid battery will read around 12.65V when fully charged and then rested.

They only time they will read higher is when "just" coming off a charge (charger or alternator). After a charge, it takes a few hours for a freshly charged battery to relax back down to around 12.65v.

13.2 volts tells me it just came off a charger, or your alternator was recently charging the battery.   

Technically anything under 12.8 volts will not charge a 12v lead acid battery, but you should be seeing around 13.5 volts or more when the engine is running.

To put it simply, with the engine running, put the meter on the chassis battery.  If you don't see around 13.5 volts, it ain't chargn'. 

For an alternator to charge, its simple, its got to spin, and the field input needs voltage.   If its spinning at idle speed., and the fields are getting voltage but the battery terminal (on the alternator)  isn't seeing 13.5 volts, then the alternator will need repaired.   

If the fields are not getting any voltage, then the regulator or the wiring is probably at fault.   

Make sure the belt is tight, my rule is with the engine off, reach down and try to turn the pulley on the alternator, if you can't spin it making the belt slip, it will generate.  If you can slip it any at all, its too loose and will not generate. 

Also, on the older rigs its not uncommon to find out turning on all the accessory sagged the voltage.   Reving the engine any at all would bring the voltage back up to around 13.5 volts.

[DaveVA78Chieftain]

As ibdilbert01 said:
13.5VDC at the battery would only be after a recent charge.
They then settle back to around 12.65.  Check it first thing the next day (or after several hours) before doing anything.  Not immediatly after having a battery charger connected.  If it still reads 13.5 then your meter is defective.
Normal charging voltage across battery with engine running is 13.1 to 14.5 volts.  The voltage has to be in the region in order for it not only to charge the battery but also act as the source for the chassis (13.1) after the battery is charged.

What model generator do you have.  Should be a lable plate on it.

Sorry about slow response.  Been working weird hours, a pickup truck kicked up a semi-tire casing on the interstate and wiped out my Honda Civic windshield, and the battery died in my van.  Sort of been occupied the last few days.

Dave

[DaveVA78Chieftain]

Most here do not know the John Deere chassis.
It has a Ford 460 engine with a Ford based charging system.
As we all know, Winnebago taps into the chassis circuits and finding wiring diagrams for earlier rigs is typically impossible.  You have to use general principles to isolate problems.
Here is the JD wiring diagram for the charging circuit.  If I have missed anything, please chime in.
http://www.mediafire.com/file/n3s0qokr91juzh8/89_JD_Charging.pdf

Dave