Radio power switch/relays?

Morich · 04-21-2020, 10:47 AM

Trying to find a point to pick up coach battery power on a 2015 Vista 31KE with 2 in the serial number. I believe this to be the correct "front end wiring" even thought the drawing does not match the breaker panel I have. My current question doesn't involve the panel but the "radio power switch". This switch is used to move the radio from start battery to coach battery and I had assumed that it would be a good place to find a connection for a small voltmeter I'm adding.
The switch is a dpdt and I have found the Carling drawing to know for sure which point to pick up but then it goes off the rails! When checking for coach battery, I don't get a steady reading of 12+ but one which seems to vary as if it is coming through some other electronics. More like 3.5 volts???
Radio works as expected on both start and coach setting but I can't pick up a connection to use for the voltmeter!
Looking at this drawing:
https://www.winnebagoind.com/diagram...ire_183023.pdf
page 3 shows the switch and then wiring which runs, near, across or through a pair of relays behind the instrument cluster of the dash.
Can anybody tell me if they use these relays or what these relays do for the RV?
I can take the dash cover off to connect, if it will actually give me a point at the relays. But that is not something I want to do if the relays are not involved.
Or another option for picking up the coach power near the dash? Everything else on the dash seems to be start battery power.

**ThomB** · 04-21-2020, 10:56 AM

When I need power I go directly to the fuse panel with add-a-fuse connectors (search on Amazon). That said it's not going to help you much with getting power from the chassis. There are some always live circuits in there that go to the chassis battery. In my case I have an Amp-L-Start between the house and chassis always keeping the chassis battery topped off when on shore power so I'd always have good current. I wired in about 4 USB and 2 additional AUX cigarette lighter adapters into the dash this way. Not sure if that's something that you could/ should do if you're looking for house battery levels.
If it were my 32K I'd be up in the cabinet where the Cable/OTA booster is. It's got 12v going to that which I assume comes from the house batteries.

Morich · 04-21-2020, 11:18 AM

Chassis battery is no problem as there are several 12 volt power points on the dash, but the coach battery is what I'm needing at the dash. There are connections in the overhead but that requires getting it down through the corner pillars and not the easy deal I'm looking for at this point.
There is a breaker panel down by the drivers left foot that has coach power as well as chassis, but totally covered and nearly impossible to access due to location. I can get in there to reset breakers but that's about all. I did get desperate and looked it over but that is when I found the drawing for my RV doesn't match the breaker panel I have.
The voltage I'm getting on the back of the radio power switch was assumed to be just straight battery but it flips up and down as if a relay was pulling/dropping off and pulling again.
That brings the question of what those two relays do and if they are involved in the radio power someway. When they dropped putting the drawings on the website, it really took a bite out of being able to trace things like this. This drawing looks like the wire loom goes close but doesn't show it it connects or just happens to pass by on the drawing.

Morich · 04-21-2020, 12:51 PM

Okay, the brain is beginning to move a bit!
With the idea of the add a fuse, I'm wondering if there is a comparable item for adding a breaker or fuse to the front of a breaker? My problem is that I have small pop out breakers, rather than fuses and I see no logical way to remove the cover to access the wiring inside.
Anybody seen a "magical" way to tie onto the front of one of these popout breakers? Looks like I could unscrew the ring to remove part of the breaker, but where does that leave me for getting power out the front?

powercat_ras · 04-21-2020, 01:46 PM

You may have two wires coming out of the Winnebago harness in the steering col area that are there for connecting a CB radio - I have not found them but believe they are hard to find based on other threads. There will be a white wire labeled EEF which will be negative ground and a yellow wire labeled EEE with 12 volt switched chassis battery power, that comes from the same breaker that power the 12 volt dash area accessory power outlets.

If you want to pick up 12 volt power from the back of the chassis / coach radio switch the wires MAY be labeled as follows: (this is how they are on my 2015 Vista)

14 Yellow MK Fused Chassis Battery - NOT key switched
14 Yellow LS Coach Battery ( from 20A circuit breaker ? )
16 Yellow GT To Radio - Memory power feed

14 Yellow LS Coach Battery ( from 20A circuit breaker ? )
14 Yellow LD Fused Ignition switched Chassis Battery
14 Yellow WN To Radio - Accessory power in

There's no 12 volt negative wire on that switch, the white wire in the Winnebago harness going to the radio connector marked MU is one.

Morich · 04-21-2020, 02:18 PM

Thanks for the added info. I may have to dig into that switch more and retrace what I found. Perhaps gave up on it too quick.
The idea is pretty simple as I am wanting to add a really cheap, really small, voltmeter and add a toggle to switch the readout from start battery to coach battery or off. So it is a three wire deal, one ground to the meter and each battery to either end of the double pole switch. With the power outlet on start / chassis battery, that feed and ground were easy but I wanted to pick the coach power off the back of that switch but when testing the wiring to the coach side of the radio power switch, I did not get solid battery but one that jumped up and down as if through a relay, etc.
Probably a good time to go for coffee and come back fresh. Three wires is way too many for my mind to work at the moment and it's getting too hot to stay there long without running air, etc. Good thing the switch is just a pop in thing that doesn't take too much to redo.
Thanks for the wire ID, I had some info on it at one time but maybe mine was not written/copied right? Will do some checking!

SLOweather · 04-21-2020, 03:15 PM

I've wanted to ID those 3 relays in our 2014 31KE for a while. I suspect one is the brake pedal (I can hear a click when I press the pedal. One is possibly for the parking brake, to interlock the jacks, slide room, and dash infotainment center. I don't know about the other one.

I needed lots of coach power up front, for added lights, sat phone, multiple cig and USB outlets, amateur radio, etc, so I ran a 30 amp circuit from the power center by the door, along the frame and into a convenient boot on the firewall with other wiring in it.

Coming down the A pillar isn't bad, with the help of a coat hanger. 3 screws and the cover is off. The tough part on the passenger side is catching it under the dash, but I've done it.

I never quite grasped why I needed the coach/chassis switch for the radio. I taped it in the coach position, put it inside the dash, and reused the hole for a light switch.

powercat_ras · 04-21-2020, 03:35 PM

You would be able to display your chassis voltage with the MK wire and the coach voltage with the LS wire, chassis and coach share a common negative ground system so you just need to pick up a good ground somewhere.

Or - You could control which one is displayed by using the coach / chassis radio switch. In that case you would connect your display to the GT wire. You could turn off the display by putting a SPST switch in the ground lead of the display.

The coach / chassis radio switch lets you listen to the radio/CD/DVD when the coach is parked without your ignition key inserted.

In a lot of WBs the dash unit also plays DVDs in standard definition (480i) and feeds the main TV thru a composite video cable. I personally use the switch whenever I'm parked so I don't have to have the key in and set to position 1 to use the radio.

Wyatt · 04-21-2020, 08:25 PM

Hi Richard,

Seriously, sleep on it, my best answers come after a good night sleep in the AM just as I am waking up...bingo. I have the answer. In fact, whenever I have an “idea” to change or install something, that’s always my course of action. Usually, the first answer is not the best...

Wyatt · 04-21-2020, 09:02 PM

Quote:

Originally Posted by SLOweather

I never quite grasped why I needed the coach/chassis switch for the radio. I taped it in the coach position, put it inside the dash, and reused the hole for a light switch.

My thought on the Coach/chassis switch was that if you’re on shoreline power for awhile, and are playing the chassis radio, you can use that switch to draw the radio power from the coach shoreline power, and not deplete the starter battery...

Morich · 04-22-2020, 12:36 PM

Well, this just gets more interesting all the time! We are not big radio users and leaving it on the coach battery setting seemed okay with us and we normally just leave the radio off. So that has led us to assume it worked when switched to the start battery, but in testing, I now find it does not power the radio when set to what we assumed was the start battery setting. I'm glad it only has two ways, up or down, as it gets confusing from there on!
My wires are the following:
Center lug left side
GT- radio power switch to radio ----Sounds okay
Top lug left side which can connect to GT
LJ--From coach battery disc relay to coach battery disc relay switch --Was not aware I had a battery disc!!! Or are they using a different name for this switch?/
Bottom lug left side
MK4---Nothing like this listed in wire ID chart?????

Center lug right side
WN--Radio power switch to radio-- sounds right!
Top right side which connects to WN if switched correctly
LS2 Not in the chart--Seems to test as start battery???? Might seem right to put start battery through to radio.
Bottom right
LD4-- not listed but tests as ground but that makes the switch put battery to the radio until switched and then it puts ground on that lead???

Not an engineer but not sure why one would want to have battery on a lead and then when removing the battery, put ground there??
Maybe picking up coach power on this switch and running six inches of wire is not as easy as going to the overhead and down the column to run 8 FEET of wire!
But it sure looked good at the time!

l1v3fr33ord1 · 04-22-2020, 02:23 PM

Morich-

If I wanted the house battery voltage, I'd pick it off the BATT BOOST switch. See this drawing, sheet 2, zone A-7, circuit LS. You could get the chassis battery voltage there too, although only with the engine running (it's ignition-switched, circuit KS).

Just above that is the RADIO POWER switch, zone D-7. Circuit MK originates at the chassis battery, and is not switched.

This diagram is for a 2009 Vista 32K (link here). Winnebago, like Ford, changes some of their wiring slowly, if at all. Looking at pre-2010 diagram sets can sometimes give answers for more recent coaches.

On the other hand, the info above may not apply at all to your coach.

Voltmeters are cheap enough. You may want to consider using two, rather than switching the inputs to a single meter. Over at iRV2 there have been some posts with nice-looking dual-meter setups.

SLOweather · 04-22-2020, 02:30 PM

Yeah, That's why I taped the switch in the coach position and stuck it in the dash. I couldn't make sense out of it, and needed the hole.

Those short doors Winnebago used for the StudioLoft do make it a PITA to work in those overhead cabinets, even with the bed removed, as in ours.

You might think about running a pair from the power center along the frame rail and into the dash, like I did. That cabinet interior comes apart easy, and fishing the wire wdown is easy though a Winnie supplied cable hole.

Actually, if you are looking for accurate battery voltage, just attach a fused pair of wires each to the house and chassis batteries under the steps. Easy run along the rail and use an unbent coat hanger to fish into the dash through that boot in the firewall. You could do it with just 2 wires and a common ground in the dash, but, as long as you are running, carry the separate grounds along, and use a DPDT switch and you'll have really accurate battery voltages.

Morich · 04-22-2020, 02:52 PM

Okay, since I'm in trouble trying to pick it off the closest point on the radio switch, next easy is the battery boost switch only the other side of the steering column. Will give it a check as my year seems to have a relay involved some way and getting to it requires removing the dash canopy. .

Morich · 04-22-2020, 04:25 PM

Okay, putting this idea back on the shelf with lots of other plans! I found I do not have the LS wire but LS1 on the battery boost switch. Looks okay and seemed to read on the little meter for both start and coach battery.
But the big hiccup came when I tried the boost switch and blew the little meter!
I found I do have a relay on the radio switch as I can hear it click from near the steering column but I'm done guessing what and how they planned to use it for powering the radio.
WOW, I just blew up a $1.70 meter and don't have another one handy----so I think I'll just quit!
Thanks for the helpful tries but sometimes it just doesn't work. I'm okay with that.

Kickenrock · 04-26-2020, 04:43 PM

In case you change your mind and try it again; I see in the picture of your dash that you have a 12V power outlet. In my 2005 Suncruiser that outlet is run off the coach/house batteries. If yours is also you could find your 12V source on the center tap at the rear of the outlet. Plugged into mine I have a two way power outlet with USB charging ports and it contains 3 LEDs red, yellow and green to indicate the battery strength.

Dynadave · 04-26-2020, 05:01 PM

In my dash 12 volt power outlet I plugged in an inexpensive dual function adapter that provides a USB port and a digital readout of the voltage at the outlet. Sweet and simple.

Morich · 04-26-2020, 07:02 PM

Both good thoughts but not for what I was wanting as I wanted to have a digital readout of both start and coach battery. All my dash 12V outlets are on the start battery. Reason for choosing this location was the easy access to the 12V battery and ground from the outlet and then assumed to be easy to pick the coach battery off the radio switch next to it. But the problem is that coach battery comes through a relay under the dash and I can't find a way to use it for my voltmeter. Part of the problem is that the drawings for my RV are no longer full sets online but more a layout of where wires are installed, but not matching the codes on the wires and not listed in the wire ID chart.
If I come back around to this, I may go with removing the dash and pick the coach battery off at the relay but before the points but that does require removing the whole dash cover over the instrument cluster and the project has not gained that much interest!
Since I'm in Texas and the virus is still ramping up here daily, I'm assuming it will be at least several months before I consider it safe to go out and about.
Too old to die this young!

Wyatt · 04-26-2020, 11:27 PM

Quote:

Originally Posted by Morich

Well, this just gets more interesting all the time! We are not big radio users and leaving it on the coach battery setting seemed okay with us and we normally just leave the radio off. So that has led us to assume it worked when switched to the start battery, but in testing, I now find it does not power the radio when set to what we assumed was the start battery setting. I'm glad it only has two ways, up or down, as it gets confusing from there on!
My wires are the following:
Center lug left side
GT- radio power switch to radio ----Sounds okay
Top lug left side which can connect to GT
LJ--From coach battery disc relay to coach battery disc relay switch --Was not aware I had a battery disc!!! Or are they using a different name for this switch?/
Bottom lug left side
MK4---Nothing like this listed in wire ID chart?????

Center lug right side
WN--Radio power switch to radio-- sounds right!
Top right side which connects to WN if switched correctly
LS2 Not in the chart--Seems to test as start battery???? Might seem right to put start battery through to radio.
Bottom right
LD4-- not listed but tests as ground but that makes the switch put battery to the radio until switched and then it puts ground on that lead???

Not an engineer but not sure why one would want to have battery on a lead and then when removing the battery, put ground there??
Maybe picking up coach power on this switch and running six inches of wire is not as easy as going to the overhead and down the column to run 8 FEET of wire!
But it sure looked good at the time!

I know you said you said that you wanted to do this project on the inexpensive side.Not sure what your budget is for this project, but many of us have employed the VictronConnect.
It will accomplish everything you want, with no more disconsternation.

Morich · 04-27-2020, 08:10 AM

My project was more driven by boredom and wanting to do some small project while in QT. The price of the little meter was good at under two dollars but that was not the primary thing. Just simple operation combined with two of my prime drivers when I mod the RV. We swap and change RV fairly often as we find life changes, so one of the things we try to resist is making any mods which are obvious to future buyers as they are often just a point to question, rather than something they will pay extra to get. Folks are kind of funny when they see something that they don't understand and an RV already has lots of those questions as they are built, so when I add other odd items it can get over too close to the cynical mind of the used RV shopper. Just easier to sell if I don't have to explain why I did something the builder did not feel needed.
Many shoppers do not know a battery from a hammer handle, so anything dealing with monitors might just make them wonder why I had so much trouble with my batteries!
So it cost me two dollars and entertained me for at least a week.
That's a pretty good return on investment!

Just the basics like the breaker panel are not what the drawings show for my year and then it involves the smaller details like having relays and wires which do not match the code list. I'm guessing my unit came along at the point where they were going to add small details and they just did not bother to add those details to drawings for that year as they moved toward posting less info for us.
The truly disappointing side is that I now KNOW that my RV is not covered in the online drawings and that does mean trouble if/when I do have problems with wiring ????
Actual results, yet to be determined!