Coach batteries not charging off alternator.

ClydesdaleKevin · January 29, 2020, 09:55 AM

So this is a new one for us. Everything was fine until we left Georgia to Arizona. Now for some reason, the alternator only charges the starting battery when we are driving, and not the coach batteries. If I hold the momentary switch on the dash, the coach batteries start to charge, but only when I hold in the MOM switch.

I'm guessing it is a bad solenoid or a blown fuse on a solenoid. Anything else it could be?

We are already half way to Arizona, at a Flying J in Tye, TX off of I-20. We've been keeping the coach batteries charged by leaving the solar panel system on when travelling, and then using the Honda genny at night with the Boondocker converter breaking "On." (We usually run off the coach batteries through the inverter, with the converter breaker in the "Off" position).

Any thoughts or suggestions?

Kev

Rickf1985 · January 29, 2020, 10:17 AM

On the momentary switch does it have a second position the other way? On mine it is momentary one way and charging the other way. You may have the diode type equalizer system that charges the coach batteries once the chassis batteries are charged. could be a loose or corroded wire on that unit. It would look something like these,
https://www.google.com/search?rlz=1C1PRFE_enUS666US695&sxsrf=ACYBGNS_7z-zLVrl9orQJJaIeN4nLlWZYQ:1580310890974&q=diode+battery+isolator&sa=X&ved=2ahUKEwjg5anqjKnnAhVSl3IEHSJlCcgQ1QIoAHoECAsQAQ&biw=1920&bih=969

Froggy1936 · January 29, 2020, 05:53 PM

Mine also has the 3 way switch, If my house batts need charged I put it on steady (opposite Mom) After the starting battery has recharged . Or if running the furnace all night Frank

ClydesdaleKevin · January 29, 2020, 08:37 PM

Mine only has a one way MOM switch...but I'm starting to suspect a short. Why do you ask? Because the dang air conditioning fans in front of the AC evaporator (the radiator thing in the front of the RV that looks like a radiator) run full blast now when the engine is running, and the AC switch on the dash is OFF. Those fans have never run before since we've owned this rig, and the AC in the dash doesn't work yet. So why do the fans come on and run constantly now when the engine is running (and only when the engine is running)?

We made it all the way to Exit 0, Anthony, TX today...and only have a fairly short 349 miles to drive to the Flying J in Eloy, AZ tomorrow. So in the morning, I'm going to follow the wires from the AC fans and see where they lead me, since the morning weather is supposed to be nice and we have a little time to kill. I'll let y'all know what I find out!

Once we wake up at the Flying J in Eloy, AZ on Friday, we only have another 50 miles or so to go and we will arrive at the Arizona Renaissance Festival!

Kev

ClydesdaleKevin · January 30, 2020, 11:47 AM

So one of the solenoids doesn't click like the MOM one does. The MOM solenoid has two fuses on top, and it works...but the bottom one, the one not clicking when you push the aux power switch, is just a silver canister and it doesn't click. I'm going to guess it is either bad, or there is a loose wire going to it. I'll finish the troubleshoot and repair when we get to AZ Renfaire camp.

As far as the AC fans running when the engine is running, I have no idea. It only does it with the engine running, not with the key in the ON position...so maybe the current intended to charge the batteries is going to those fans instead?

I found the fuse for those fans under the dash...so after I start the rig this morning, I'll pull that fuse and see if the fans are still running. Bizarre!

Kev

DaveVA78Chieftain · January 30, 2020, 02:56 PM

Your handle says you have a 1995 Itasca 32RQ on a Oshkosh chassis however the 1995 brochures says the Oshkosh was only on a 34RQ. Here are the wiring diagrams for a 1995 Itasca Suncruiser 34RQ (IKG34RQ)

If your MOM switch is just a NORM/MOM switch and is not a MOM/Neutral/Dual switch then you most likely have a diode based battery isolator. It may have died. It charges house battery anytime the engine is running.

Typical Diode based Battery isolator

Battery disconnect relay with 2 mini fuses attached (AUX Battery Disconnect)

Typical Battery Mode Solenoid (MOM switch)

There are both 3 post (ground through case) and 4 post versions of the Battery Mode Solenoid

DaveVA78Chieftain · January 30, 2020, 03:24 PM

I forgot to mention, the AUX Battery relay works differently from a Battery mode relay. It only has control voltage to it when you press the ON/OFF switch then the relay latches into the ordered position. This way you can set it to either ON or OFF without having to have power to it all the time.

Rickf1985 · January 30, 2020, 06:39 PM

As Dave siad, The one you say is clicking is the battery shut off switch. So when it clicks the battery power to the coach should be off completely, nothing should work at all. If everything is wired correctly that switch disconnects the batteries from the coach. And from all charging! now I don't know what you have done with the solar but that switch in the off position will kill the main converter from charging the batteries also since they are disconnected from the system. On the Winnebago that switch is on the dash with a little light next to it and the light will be on the whole time the battery power to the coach is turned on. (Unless your bulb housing broke like mine) If the other solenoid is not clicking see if you are getting voltage to the small terminal when the switch is pushed. If you only have a one way switch then it should not stay on unless the switch does not spring back to center. Is it a momentary switch or an on/off switch?

ClydesdaleKevin · January 30, 2020, 08:39 PM

Quote from: DaveVA78Chieftain on January 30, 2020, 02:56 PM
Your handle says you have a 1995 Itasca 32RQ on a Oshkosh chassis however the 1995 brochures says the Oshkosh was only on a 34RQ. Here are the wiring diagrams for a 1995 Itasca Suncruiser 34RQ (IKG34RQ)

If your MOM switch is just a NORM/MOM switch and is not a MOM/Neutral/Dual switch then you most likely have a diode based battery isolator. It may have died. It charges house battery anytime the engine is running.

Typical Diode based Battery isolator

Battery disconnect relay with 2 mini fuses attached (AUX Battery Disconnect)

Typical Battery Mode Solenoid (MOM switch)

There are both 3 post (ground through case) and 4 post versions of the Battery Mode Solenoid

It is indeed a 34RQ...I'll have to change that on my profile.

That said, I looked all over for one of those battery isolater thingies, and I can't find one anywhere! The cables from the batteries seem to go right to the box in the front compartment that has the two solenoids. Everything WAS working just fine, so I'm at a loss.

Does the wiring diagram give any clues as to where the isolater might be? Because I downloaded and POURED over all four wiring diagrams, and I'm not seeing ANY diode based battery isolater in any of the diagrams. Nada.

Kev

ClydesdaleKevin · January 30, 2020, 09:01 PM

Quote from: DaveVA78Chieftain on January 30, 2020, 03:24 PM
I forgot to mention, the AUX Battery relay works differently from a Battery mode relay. It only has control voltage to it when you press the ON/OFF switch then the relay latches into the ordered position. This way you can set it to either ON or OFF without having to have power to it all the time.

This is the switch/relay that doesn't seem to be working. No click at any solenoid when the switch is depressed in either direction. I am getting a click when I hit the MOM switch...and when I hold the MOM switch, my volt meter jumps and shows charging voltage going to the coach batteries when the engine is running...but only when I'm holding the MOM switch. As soon as I let go, the charging voltage to the coach batteries stops, although the charging voltage to the starting battery stays constant.

Kev

ClydesdaleKevin · January 30, 2020, 09:05 PM

Quote from: Rickf1985 on January 30, 2020, 06:39 PM
As Dave siad, The one you say is clicking is the battery shut off switch. So when it clicks the battery power to the coach should be off completely, nothing should work at all. If everything is wired correctly that switch disconnects the batteries from the coach. And from all charging! now I don't know what you have done with the solar but that switch in the off position will kill the main converter from charging the batteries also since they are disconnected from the system. On the Winnebago that switch is on the dash with a little light next to it and the light will be on the whole time the battery power to the coach is turned on. (Unless your bulb housing broke like mine) If the other solenoid is not clicking see if you are getting voltage to the small terminal when the switch is pushed. If you only have a one way switch then it should not stay on unless the switch does not spring back to center. Is it a momentary switch or an on/off switch?

The solenoid that is clicking is the MOMENTARY solenoid. When I push in the MOM switch, charging voltage is applied to the coach batteries and the starting battery with the engine running. When I push in the Aux battery switch, in either direction, either "Off" or "On," there is no click at that solenoid, and nothing changes.

I'm getting 12 volts to all coach systems though, so I'm not sure what the Aux Battery switch does. I couldn't find any sort of diode based battery isolater when I looked this morning...and I poured over the wiring diagrams Dave supplied, and there doesn't appear to be one at all in the diagrams.

Kev

ClydesdaleKevin · January 30, 2020, 09:08 PM

I have no idea still if the A/C fans coming on is related to my charging issue...but when I started the coach this morning, the fans came on again. (They don't come on with the key in the only position...only when the coach is running). I pulled the fuse for the A/C fans, and they stopped. I traced their wires and didn't see any shorts...so I have no idea why they suddenly decided to start running when the engine is running...lol!

I'm going to leave the fuse removed for now, since I haven't gotten around yet to getting the dash A/C working, and it isn't very high on the priority list.

Kev

ClydesdaleKevin · January 30, 2020, 09:12 PM

Oh yeah...I just changed my profile to provide the proper designation for our coach: G34RQ

Kev

Rickf1985 · January 31, 2020, 08:28 AM

Ok, So the momentary switch is working the way tit should be working. If it was staying on before then it was sticking. The aux battery switch is not working and you should look into it. It has failed in the on position lucky for you. I would guess one of the fuses has blown. That switch works off of the coach battery power so if the coach batteries are dead it will not work but this is obviously not your problem. It could also be a switch problem where the switch is not getting power but checking the fuses is a lot easier to do than tracing the wires on the switch. That you can do when you get to your next faire.

On mine the momentary switch has a second position where you switch it to the left and it stays there and that will charge the batteries while running. I am not sure if this was factory or added in since the switch has definitely been changed and the positions were reversed but I think the original positions indicate that it did that from the beginning.

DaveVA78Chieftain · January 31, 2020, 09:13 AM

On pdf page 9 (Oshkosh page) of the Front end wiring diagram (114153) it shows the AUX Start switch P/N as 108357-09-000. Referring to the Winnebago Catalog pdf page 77, that is listed as Switch-Rocker, SPDT On/None/Mom 3 Term. That tells me it is a 3 position (On/Off/MOM) switch. If it actually is a 3 position switch, then my first guess is the "ON" side of the switch is broken.

My thoughts about the battery isolator are based on the Winnebago Service guide which is how the "automated charging feature" is implemented.

wae · January 31, 2020, 10:33 AM

I had a similar problem with my battery switch - no house battery charging while driving, but I couldn't hold down the momentary switch and get power through that system. My coach is probably somewhat similar to yours, so I'll make some sweeping assumptions, but your mileage may vary...

If you want to know the details read below. If you only care about arriving at the destination, skip down to the TL;DR section below.

On mine, I have two switches for the batteries one is a simple on/off for the house batteries which is on the dash. I've heard of that being called the "salesman's switch" or whatever and being located by the door on some chassis. That's the Battery Disconnect switch which activates the relay on page two of the "Front End Wiring Installation" wiring diagram (top left, G7 square, P/N 86273-01-000). When you flip that switch, you should hear some pretty solid clicking or popping. The solenoid below it at F7 (P/N 8188-01-000) is the "battery changeover" which should be the one that connects and disconnects the alternator/chassis battery from the house batteries. The more complete wiring picture is in the "Body Wiring Diagram" document on page 1 in the bottom-left but in this representation the "changeover" is now the "battery mode" solenoid and is on the top of the picture.

"In Theory" that purple wire that's labeled as "14 PUR, LR" on the diagram goes up into the chassis wiring harness which brings us to the third wiring diagram "Automotive Wiring Diagram" which is a bit harder to follow. Page 1 at about C3 is our friend the SOLENOID and you can see where the chassis battery positive connects to the "ISOLATED STUD (LOCATED IN BATTERY COMPT) and then continues to the right side of the solenoid (per the drawing. It may or may not be the actual physical right side). You have a nice, thick probably red cable that goes from the left side of the solenoid down to the left side of the BATTERY DISCONNECT which from there goes to the coach battery systems eventually. If we follow the 14 PUR wire out the top of the solenoid we go all the way to the left, sail off the edge of the earth and find ourselves on page 2 of the Automotive Wiring Diagram where it quickly succumbs to a quagmire of purple wiring. (side note: There is a special place in hell for whomever decided that every wire on the chassis side would be either purple or green no matter what it's actually supposed to be for. In an automotive situation it is so much easier to be able to just look for the green-black wire as opposed to this mess where EVERYTHING is the "purple" wire. But, I'll get off my soapbox now....) Deep breath.

So, we're following 14 PUR after it fell on to the second page of the PDF (which is still actually considered page 1 as far as the wiring diagram is concerned) and we're in sector E9. We're looking for the 13th connection from the top of the page. Keep following it to the left until it bends up and we go upwards and onward towards H12 where we find a connector. This connections to WIRE ASM-IP, CENTER which is located BELOW DASH POD. This tells us that we need to move to page 2 sector F6 or page 4 sector F6 which will depend on options usually, but make note that we're following pin number 5.

The difference between page 2 and 4 appears to be the presence of a CD player (look at the notation in E5/E6). But I don't think that matters for this connection. Either way, it scoots to the left and ends up at the "Aux Start Switch" in this diagram. On my coach, it actually terminates at a switch that has multiple positions - a momentary on plus a constant on. So, first off, you can try to pull that wire from the switch and give the circuit +12V directly and see if your solenoid pops. In fact, I would actually first to to the solenoid directly (should be in a big black box behind the grille) and push the +12V right there at the purple wire and see if it engages the solenoid. Oh. I guess that instruction would be a bit clearer if they used different color wires for different functions. So we're looking for the purple wire that is basically all by itself on the body of the 'noid between the two large battery cable posts. If that pops with voltage applied, then the solenoid is probably good. And since it appears to be connecting the two systems when you press the switch, then my guess is that it is probably good.

Back to our Aux Start switch, then. Sheet 2 which is PDF page 3 of the Automotive Wiring Diagram. Our aux start switch is up there in G8 and the "KE" wire on pin 3 is the feed that goes from that switch to the solenoid. Let's follow some more wires. We've got pin 1 which is the purple wire. That one is attached to both the Aux Start and the Radio Power switches and goes to the connector there on pin number 1. Back to Sheet 1, H12. We follow that down and over to the right side of the page and go to PDF page 1 and look for the bottom-most connection coming from the left side. We wind up at a fuse over on C1 and come out the other side of that fuse on a blue wire. So, stop collaborate and check that fuse real fast. If it's good, we'll keep rolling and follow that blue wire on the diagram down and over to B3 where we arrive at the battery disconnect switch again. Going back over to the Body Wiring Diagram on page 1 in A7 we can see that this ties in to the power that goes to the 12 volt house fuse panel and the generator's starter. So this is a house +12V feed going in to this switch.

Back to the switch, we'll look at the third and final position which is the purple wire. Ha! Just kidding! They're ALL purple! This is the shade of purple that connects to pin number 3 on the switch which feeds back to the WIRE ASM-IP, MAIN connector at F7/F6 on pin number 4. So back to Sheet 1, H12 (which, again, is PDF page 2), and we follow that down and over to a bunch of different splices and connections. We've got the vacuum pump, leveling jacks, rear monitor (backup camera), the fuse box, and it sails off the edge of the world to PDF page 1. Counting from the bottom, we are following the 6th connection. Following that all the way over and down, we're back to a fuse box that's on PDF page 1, C2. Check that fuse as well while we're here and then we cross over and head back to the left again, falling off the page and going down to PDF page 2. This time, we're on the connection that is 3rd from the bottom. Following that back to the left, we stop off at the electric step and continue right back to the WIRE ASM-CHASSIS on pin number 5.

Now we've got some detective work to do to figure out where the heck this goes. The note says that it is physically located on the bottom of the front electrical box and the note tells us to check WIRING DIAGRAM-BODY for "ADDITIONAL INFORMATION". So, back to the Body diagram on the first page in E5 we have our connector. So from pin number five we just trace the purple wire. Oh, wait. 8 of the 13 wires are purple, aren't they? Alright, so stepping back off the soapbox and tracing connection number 5 we go off to the right and end up at the electric step. Which seems a bit anti-climactic.

Employing a bit a guesswork, though, my guess is that the purple wire there on pin number 5 is probably chassis +12V that is powered in "run" but dead in crank and acc.

-------------------------------------------------------------------------------------------------------------------------------------
ENTER THE TL;DR SECTION HERE!
-------------------------------------------------------------------------------------------------------------------------------------
So what does all that garbage distill down in to!? Okay, pretty simple: You've got a switch that has three wires. Pin 1 is +12V in from the house batteries. Pin 2 is the feed to the solenoid. Pin 3 is +12V when the ignition switch is in "run". Probably.

My switch is momentary on the left, open in the middle, and constant to the right. This means that when held to the left, I feed +12V from the house batteries to the solenoid powering the solenoid from the house and connecting the house batteries to my chassis battery. When I leave the switch in the middle, the solenoid is disengaged at all time. When I push the switch to the right, I feed +12V from the chassis charging system to the solenoid. This means that I can leave the switch in the right position at all times (in my case, the label on the switch is "dual") and when (and only when!) the ignition is in the "run" position, my two 12V systems will be connected. When I turn to "crank", the solenoid is de-powered and when I turn the ignition "off", the solenoid is de-powered which isolates the sets of batteries.

If your switch is momentary only, then your two systems are always tied together when the ignition is in "run" only. If there isn't enough chassis battery power to start the vehicle, you can hold the momentary switch down which uses the house batteries to both energize the solenoid and connect the two sets of batteries.

So, what's wrong here?

You actually have a switch that is momentary on one side and "regular" on the other side, like mine, and you just need to put it in the "dual" position.
There is a fuse blown on the chassis electric side. Check those ones that we found on our excellent adventure through the wiring diagram to see if any are bogus.
The switch itself is faulty. Isolate the switch by pulling the switch from the connector and jumping the wires for pin 3 and 2 when the ignition is in "run" and see if the solenoid pops. If yes, but the switch doesn't do that, get you a new switch. Feel free to have the coach cut its own if you think it will learn from its mistake.
Loose wiring somewhere.
Bad solenoid (but it sounds like it's working peachy keen fine when you hold down the momentary switch, so super duper unlikely).

Anyway, those are my guesses.

DaveVA78Chieftain · January 31, 2020, 10:38 AM

Be sure and check the fuses on the chassis fuse panel with a Volt meter. Power to the Battery mode switch (ON/OFF/MOM), circuit KE, comes from that fuse panel. Not sure which one but that is the source for circuit KE (RUN ONLY POWER SOURCE). This setup always energizes the Battery mode solenoid when key is in RUN. Since the relay works in MOM, then either the Mode switch is bad or there is no power to it. The MOM position has a different power source. At least that is what the wiring diagrams tell me.

PS: Both Wae and I posted at the same time however we both are basically saying the same thing.

DaveVA78Chieftain · January 31, 2020, 11:06 AM

The AUX Battery ON/OFF relay issue however is most likely the relay itself. The 2 large contacts have most likely fused together and the relay is constantly ON. This is a common problem with them.
Power to the switch comes from the fuse mounted on the relay on the battery input side of the relay (short cable from Battery mode relay). Control power is routed from the switch back to the relay via the 2 lead connections on the side of the relay.
1. Control power from the switch is only present as long as you are depressing the switch. That signal cause the relay to change position and mechanically latch into the new ordered position. No constant control voltage is required to keep it in the ordered position.
2. Control selection (ON/OFF) is achieved by reversing the polarity of those 2 lead connections on the side of the relay.

Again, the common problem is that the main contacts inside the relay that pass the battery power through the relay FUZE together resulting in the relay staying ON all the time.