1987 Chieftain Aux Battery switch on dash..how does it work?

Newbie...

I have a 1987 Class A Winnebago Chieftain 31footer...just bought, and when I got it home, I was curious about the rocker switches on the dash that are related to batteries.
The one on the left side, is called the Aux. Battery Shutoff, and somehow when "working" with it, it starting getting hot, and upon feeling the group of wires behind it, nearly burnt my fingers..upon pulling the switch out, I found that a lot of it is melted, but no real damage to the wires yet. I've looked everywhere here and no one has anything like it, other than Radio Shack, who has a toggle-type, instead of the rocker that I now have. It has I believe six blades on the rear of the original, and there is a small indicator light mounted just to the left of it...

I later found that it is some kind of momentary switch, and don't know if I caused it, but I was trying to "latch" the switch by continually pushing it to the left. So I don't know if maybe that had something to do with it shorting and melting...
Can anyone advise me on this? And where I might get a suitable replacement? Possibly how it works and how the wiring is laid out?
Thanks for any advise...

Tim in Chattanooga

If it is like mine it is intended to be a momentary-on switch for a solenoid to bridge the house and chassis battery, with the intent being to use the house battery back as an alternative source for starting the engine if the main battery is low/dead.  So if it is hot/almost melting I think current through it is too high, and it should not be "latched".  I'd definitely leave it open or disconnect wire if that hot until I could check it further.

Thanks for the info...so, on yours, does the switch work in the "momentary" phase when pushed to the left? And then does it return to center? And is there any purpose of it going to the right, whether momentary or latched? I think the rear of it melted, due to me fiddling with the switch, and holding it down to the left, trying to make it "latch" (which I didn't have a clue what it was supposed to do...read about it later...duh! haha) So now, it does not have any "action" to it. If I have to adapt another switch for it, I'm trying to wrap my brain around how the wiring should be. Of course I have made a drawing of the hookup now, so I if not an exact match, I'd have to figure out which wire does what...

Thanks again..
Tim

I used to have a 1970s vintage Winnebago.   On that motorhome, the battery switch was a dual momentary - you could push it to the left or to the right, and it wouldn't latch in either position.   As soon as you released the switch it returned to the neutral position.

The switch activates a relay that connects your house and chassis batteries together.    When you release the switch the relay also releases.

The reason you can push the switch either way is because one way powers the relay from the house batteries, the other from the chassis battery.

Powering the relay from the house batteries is obvious - so you can jump-start a dead chassis battery and start the engine.   But why you might need to go the other way and get power from a good chassis battery to jump-start a dead house battery may be less obvious - it's so you can start your generator, which is powered from the house batteries.

The relay is actually a Ford starter relay and is rated for only a few seconds operation at a time.  The coil will overheat and short if it's left on for any period of time.

If your switch latches in one position, then instead of a Ford relay you're supposed to have one that looks the same, but is rated for continuous operation.

I suspect you have a Ford starter relay, whether it's the proper one for that model or not, and the coil has overheated and shorted out from a long activation.   This in turn will draw too much current through the switch and it's related wiring.    I suspect this is what has happened to your switch.

wow! Thanks Lou...great info. I'll be looking into that...

Tim

Solenoid pictures


Hopefully, I've gotten the link thing right, and you can view pictures of the Aux Batt. Solenoid I took out...

Temporarily I wired in a Radio Shack switch to the Aux. Batt. Cutoff position, then went back and hooked up battery neg. cable. House lights came on, but nothing else seemed amiss...went back to feel of the wires on the switch...no heat...I then flipped the toggle (MOM) to the left, and did not hear any solenoid noise. Some time later, still no heat on any wires at the switch. I then flipped the toggle to the other (MOM) right side, and same results. I never did get a click or clunk sound from the Aux. Solenoid.

Upon further inspection into the compartment, I found only one battery hooked up, and the neg. post was grounded to the frame only. The positive post had one lead going to the right side (facing it) of the solenoid, and another heavy red lead off of the solenoid going away towards the frame. There was no cable attached to the left side post of the solenoid. Two small black wires (from the frame area) were tapped to the two small taps on the front of the solenoid. I noticed that from each fuse there came a wire that were both in rough shape wrapped around each large post (again, LEFT side had nothing attached to it). One side had a 30Fuse, the other had a 25.
I also found there were three large capacity wires with ends cut, just laying in the area, which I had found a few days earlier and proceeded to tape them up to keep from grounding on anything...they come from the frame area as well, and one ties into a smaller wire that pairs up with another that run up into the wall to the right of the coach's entrance door...

So..any thoughts on this? I wonder if I might be able to find something in print that would detail what these wires are?

Wow, what a mess.  The large wire disappearing under the chassis should go to to the chassis battery's positive terminal, or to some other point like the starter that connects to it.

Then you need to supply 12 volts from the center of the switch to one of the small terminals, and connect the other to chassis ground.

Have you tried calling or writing Winnebago?  They're usually good about supplying information.

Dang - should have moved this one to the Winnie forum a couple of days ago  :

If you push the switch while the generator was running, would explain the overheating. The manual specfically warns NOT to do this since it can damage you chassis alternator. I can explain to you how does it really works according to the manual, once I get home and post it here word by word.

Here's what the switch in question does in my 89 Sunflyer.  Three positions, a momentary position to the left connects the coach batteries to the engine battery for a boost.  The centre position disconnects the coach batteries from the alternator charging system while the engine is running.  The right latching position connects the coach batteries to the alternator charging system while the engine is running.  When the key is off and the engine not running, even though the switch is in the right latched position, the coach batteries are isolated from the chassis battery.  As a precaution, I always return the switch to the centre off position before I shut down the engine if I have been running, charging the coach batteries.  I learned to do this after toasting some wires in my old 78 Minnie Winnie.  Hope this helps explain the purpose of the mom/dual switch. 

I also have an Aux Battery switch which has an indicator light below it.  On my coach this switch is semi automatic.  It is momentary to both sides.  On by pressing & releasing to the right, and off by pressing and releasing to the left.  In the on position, all lights etc are powered.  In the off position, all power is shut down.  This switch controls a latching selenoid which in turn controls the power coming from the coach batteries/convertor.  However, you can not shut down the coach power if you are connected to an external power source, ie. shore power or generator, and probably solar if you have it.

Hope this helps
 

Fred, bluegrasser...

No, I didn't fool with the switch while generator was running. It was after I parked in driveway, and motor shut down. At the time, I thought it funny that it didn't "latch"..haha...I should have read instructions first, huh? But I'm not sure when problems began...after talking to Winnebago techs a couple of times, and got some good diagrams emailed to me (thanks guys!) we've come to the conclusion that someone before me pretty-much eliminated the usual setup, by bypassing the relay. I found that POS from Aux. Batt. was attached to the right-side post of the relay, along with the feed (red) going towards the frame. The left side post had nothing attached to it. The small wires were connected to the front small taps, and I found a 25 and 30 fuse in the holders...
I've put in another switch at the dash (MOM) off (MOM), but I'm thinking I might just leave well enough alone and wire like it was, and putting a quick-disconnect at the battery post, since it's easy to get to at the step...
But, if I could get it work as it should, that would be nice too. Not a great tech at the electricity part of this, but that don't stop me from trying...haha...I've managed to fix a lot of things over the years, and yes, I've had my share of "failures" too...But there's nothing like the feeling of fixing something yourself, and understanding it at the same time...
And yes, my Aux. Batt. switch has an indicator light below it as well...
Keep the ideas coming...
Thanks so much.

Well, making some slow progress on this, until the tranny just went south on me. So it's now in the shop for that...
But after that...

I don't have the house batteries hooked up at the moment. But I was starting to put things back to the way it was originally (not so sure good idea, but I'm trying to trace all wires down to make sure all is correct). So I have the relay hooked up, but the only Battery lead hooked up to it (on the right side lug) is the big red feed that comes from the chassis. Again, no house battery hooked up. So last night I was piddling with it, the engine was running, and clicked on (left side) the DUAL switch, and the house lights came on. I metered from the big lug with the Chassis Red cable and to ground and was getting 12+ volts. I would click off (middle) the switch and the house lights went off. Is this correct? I'm assuming that the DUAL mode let the output from the alternator come to that relay and was powering the lights. Motor off, and lights went off.
Winnebago folks were kind enough to email me several pages of wiring diagrams, and that has helped greatly, but I'm still a bit confused in some areas. When I first found all of this, I figured that someone had bypassed the relay for some reason, so I'm not sure what all might have been changed...
At this point, I don't even know that the Relay is good, but I did take it apart, and everything looks good in it. The two small contacts on the front wired to the coil in the bottom of the unit have no break in continuity. So I really can't see any real physical damage to it...

Any thoughts on this? Am I going in the right direction?

Modrob:  I'm surprised to read that your house lights came on when the house batteries were not installed.  It sounds like your dual switch is indeed supplying power in the dual position, but to what?  It is my understanding that all 12 volt power passes thru the house batteries when running on battery, shore power, generator, engine alternator. etc.  The dual switch is designed to charge the house batteries from the engine alternator, but I wouldn't have thought it could power up the lights etc. without the batteries in the circuit.  Maybe someone else on this forum can enlighten both of us.

bluegrasser said:

It is my understanding that all 12 volt power passes thru the house batteries when running on battery, shore power, generator, engine alternator. etc.  The dual switch is designed to charge the house batteries from the engine alternator, but I wouldn't have thought it could power up the lights etc. without the batteries in the circuit.  Maybe someone else on this forum can enlighten both of us.

Click to expand...

Not sure what you mean by power "passing through" the house batteries in this case.  If the switch is wired to connect the alternator to the house batteries for charging, (whether they are physically there or not) then that charging current/voltage is available to perform all duties of the house batteries.  All connections are made and switched on the positive side of the batteries. 

The alternator voltage/current does not pass through the house batteries to reach the loads.

Thanks again for your continuing support...

So once I get back to this problem (after the tranny is rebuilt), am I correct when I think that if I'm motoring down the highway, and I've got the DUAL switch engaged, charging the house batteries, then if I'm running the generator too, am I doing damage to the alternator, or anywhere else? I keep going around in circles reading the manual and such...I may have the wild idea that if the alternator is charging the house, and the generator is too, there would be some kind of problem?

We frequently run the gen set in the afternoons for the house air when we're on the road.  Never had a problem with the alternator and Xantrex charger interfering with each other by charging the batteries.

Lou:  Thanks for the help, I knew someone out there would know a whole lot more than me.  Since there are only 2 cables connecting the batteries they can not pass the power "through" to the system.  One is a neg. ground, and the other the pos. which is connected to the busy little selenoids which direct the power to or from the batteries depending on switch positions.  I assumed that since the battery neg. is connected to a stud right in the battery compartment that the battery would need to be in the circuit for anything in the coach to work, but obviously there are other neg. connections which will allow the system to work without batteries installed.  The batteries are there to supply power when no other source is available.

Once again, thanks for the help.  It' a wasted day if I don't learn something new. 

modrob said:

So once I get back to this problem (after the tranny is rebuilt), am I correct when I think that if I'm motoring down the highway, and I've got the DUAL switch engaged, charging the house batteries, then if I'm running the generator too, am I doing damage to the alternator, or anywhere else? I keep going around in circles reading the manual and such...I may have the wild idea that if the alternator is charging the house, and the generator is too, there would be some kind of problem?

Click to expand...

On my Itasca Suncruiser, when I run the genset with the battery switch in the DUAL position, often my engine battery light comes on. I just disengage the DUAL switch and the light goes out. I don't know whether this causes any harm but I always try to remember to disengage the DUAL switch when running the genset. BTW, I would much rather charge my batteries with my genset/3-stage charger than the alternator, so I see no reason to have the battery switch in the DUAL position when the genset is running.

On the same subject i have a 87 chieftan 27 foot same switches and i have broken one.  Well i have disconnected the wires and now have no idea which ones go were.  I have 3 wires coming off each switch.  The one on the left has orange, brown,gray. the one on the right has orange white, black.  anyone have any ideas on which goes where?  Thanks,

Chris Wilson
816-985-0129

Hi Chris!  It's very nice to have you join us here and please feel welcomed    If nobody has any ideas, see if there is a wiring diagram for your year/model (resources sticky above), or call Winnie customer relations and they can most likely email/fax/snail mail you the relevant wiring diagram (or answer your question.)

Let any of the staff know if you have questions about forum operation and we certainly look forward to your being active on rvforum!