Multiplex Issue

[Jeff Watt]

Having a multiplex issue :

A week or so ago all 12v power went out. I assumed that while cleaning around the front step I managed to hit the salesman switch. I cycled it and everything came back on. Today again cleaning in the area I was careful not to hit it with the vacuum head and I don't know if I did or not but again all 12v power went out. To shut it off the switch needs to go up, so it seems to me that it is more difficult to do. Nevertheless I switched it back on and things work.

BUT, the front Multiplex wall plates are not lit up. There are two on the ps and on on the ds AND the switches do work, i.e. I can turn lights on and off, raise/lower awnings (and I assume the slide functions work). However the Master switch does not stay on. If I switch it, then the rest of the light circuits in the coach go out, but it doesnt stay on.

I looked in the bedroom closet and there are no specific fuses for it other than for its CPU. Are there fuses in the black box control modules? If so would there be a fuse only for the backlight of the switch plates? I kind of doubt it.

I looked at the wiring diagrams, but that didn't help me.  

So, while it is a problem to not have them backlit, they are working. Could it be something else. It seems too coincidental that in both instances using a hand held vacuum in the vicinity of the switch causes all 12v power to go out. - I now don't vacuum in that spot - also I guess a cover over the switch might be wise.

Any suggestions are appreciated.

Jeff

[Lee Welbanks]

As far as the 12 volt saleman switch, it energizes a solenoid that is in the front run box under the drivers side. It sounds like the solenoid may be on its last leg. What a lot have done is connect both 12 volt mains to the same stud which takes the solenoid out of the loop.
The back lights on the switches I haven't got a clue, is it just the front ones or all of them?

[Edward Buker]

Jeff,

The multiplex system typically works by sending coded digital signals down a set of common wires to be decoded by integrated circuit modules that decode what is supposed to happen. Depending on how complex the digital code is that activates the circuits you can avoid errors in the outcome but the coding and decoding circuit complexity adds cost. This is all a compromise in design. This is not a perfect science and when you have a unit, like a hand held battery operated vac, the brushes on the motor arcs some and any arcing sends out a broad spectrum of radio frequency noise that can attach to the wires and head for the decoding circuits.

 My guess is that if you stopped using the vac, like you did, you will not likely have an issue in the future. You might try another vacuum and see if you can find one that does not cause this issue.

The master switch is probably a separate issue and I would change that unit out given they have been problematic for others.

Later Ed

[Joel Ashley]

Yes there is a backlight fuse, 5 amp, in the Multiplex Control Master, Jeff.  Click on the photo to get a larger version.

-Joel

[Lee Welbanks]

Yes there is a backlight fuse, 5 amp, in the Multiplex Control Master, Jeff.  Click on the photo to get a larger version.

-Joel

Thanks Joel,

I'll have to look at my multiplex panels, have a whole wall of them in bedroom closet. Great pic.

[Jim Nichols]

If all else fails disconnect the house batteries and either cover the solar panels or pull the fuse located at the batteries. Wait no less than 30 minutes or longer if needed.  That is Monaco's solution to reset the multiplex control. Just a suggestion.  Mike Humble had issues at Hilton Head and that's what they said to do.  I could not find fuses for his problem.

[Lee Welbanks]

If all else fails disconnect the house batteries and either cover the solar panels or pull the fuse located at the batteries. Wait no less than 30 minutes or longer if needed.  That is Monaco's solution to reset the multiplex control. Just a suggestion.  Mike Humble had issues at Hilton Head and that's what they said to do.  I could not find fuses for his problem.

Did that multiplex reboot solve Mike's issue?

[Mike Humble]

Yes it did.  I had lost right tail light and upper rear clearance lights as well as signal to tow.  We disconnected batteries and solar, let sit 30 minutes and reconnected and all has worked well since.  Go figure.
Mike

[Joel Ashley]

That may have been the chassis ECM that was reset for Mike's fix.  The multiplex is house-related.

Joel

[Jim Nichols]

Joel we did not disconnect chassis batteries only house even though it was clearance lamp issue.

[Lee Welbanks]

Yes it did.  I had lost right tail light and upper rear clearance lights as well as signal to tow.  We disconnected batteries and solar, let sit 30 minutes and reconnected and all has worked well since.  Go figure.
Mike

Now one would think that if they (Monaco) knew that some of this would need rebooting they would make it easy like turn off some main switches, but no you have to unhook everything.
With my Beaver it states in the manual that the battery disconnect switches shut down everything except the motor, trans ECM's and a couple other items, not true the inverter is still live until you turn it off at the controller inside. Found out by accident was leaving the coach in storage everything switched off and I forgot something inside, so went back in and noticed that the microwave clock was still on, turned off inverter and no more battery drain.

[Jeff Watt]

I was out for a while today and when I came back the backlit of the switches was again working as normal. No explanation  :-/.

The other information is stored for use.  I'm going to check a couple of other things. Joel, I'll re-look at fuses as i dont see that particular fuse and besides why would only a couple of them go out. I'm sure mine is like Lee's as there is a whole bunch back in the closet and it doesn't look like your picture. Will post picture later.

Takings Ed's advice, I don't think I will put the Dyson hand held vacuum anywhere near the cut off switch. These couple of instances were the only times I had ever used that switch - I'm thinking of finding some kind of plastic cover for it so it doesn't get accidentally switched.

Jeff

[Lee Welbanks]

I was out for a while today and when I came back the backlit of the switches was again working as normal. No explanation  :-/.

The other information is stored for use.  I'm going to check a couple of other things. Joel, I'll re-look at fuses as i dont see that particular fuse and besides why would only a couple of them go out. I'm sure mine is like Lee's as there is a whole bunch back in the closet and it doesn't look like your picture. Will post picture later.

Takings Ed's advice, I don't think I will put the Dyson hand held vacuum anywhere near the cut off switch. These couple of instances were the only times I had ever used that switch - I'm thinking of finding some kind of plastic cover for it so it doesn't get accidentally switched. What is the replacement for this "salesman" switch?

Jeff

There are a bunch of threads in these sites about by passing the switch, the switch really doesn't serve any purpose, I have never used mine some say that the switch is there so when the sales person wants to show a coach they can have all the lights set to on and only have to hit one switch when entering the coach. A lot of the time the solenoid fails, when this happens its time to take it out of the loop.

[Edward Buker]

Jeff,

It may not be the Dyson, it can be any electrical noise that gets into the chassis harness which is what can make you a little crazy with these things. When the solenoid salesman switch changes state (gets switched) it certainly puts a good voltage spike on the DC harness that could give the multiplex system some problems. Anytime a connected magnetic field collapses it produces a voltage spike and current flow. I think what you will learn over time is what causes these problems with the multiplex system and how you can recover by resetting it.

Later Ed

[Gerald Farris]

Joel,
The 08 Marquis has multiplex systems for the chassis as well as the house.

Gerald