BAC Forum

General Boards => Technical Support => Topic started by: Bert Garnes on September 19, 2015, 02:04:42 PM

Title: Lights in bedroom out. Circuit issue?
Post by: Bert Garnes on September 19, 2015, 02:04:42 PM

Hi knowledgeable Beaver owners.  Hoping some one can help.  When we took our coach out and the bedroom overhead lights would not go on.  Here is what we did.

1. Changed the fuse.  Pushed the multiplex button to turn on lights on pop. Fuse busted.
2.  Shut both overhead lights off at the base. Replaced fuse.  Expected no lights but also no pop on the fuse.  When we pushed the multiplex button, sure enough the fuse popped again. 

We stopped at this point.  I don't know enough about electrics but I think the short is in the multiplex, hubby says it could be one of the light fixtures.  I am not sure what to do next.  Do we replace the overhead lights with LED (we did this in the bathroom) or is it something in the multiplex.

Coach is a 2006 Monterrey.  We are newbies and store coach at a facility.  Primary use is for vacation.

Kris

Title: Re: Lights in bedroom out. Circuit issue?
Post by: Fred Brooks on September 19, 2015, 03:10:40 PM

               Hi Bert,

      From your discription, It sounds like the issue is between the light and the multiplex controller. To futher t-shoot if your inclined would be to remove the light and disconnect the power wire to it and try the m-plx switch again. if the fuse blows again then disconnect that light power wire at the contoller so we can divide and conquor. m-plx controllers rarely go bad.   Regards, Fred

Title: Re: Lights in bedroom out. Circuit issue?
Post by: Russ Mann on September 20, 2015, 01:37:33 AM

Hi Bert,

Welcome to the Beaver World.

I'm fairly sure you have a bad output on channel six of your multiplexor. Channel six on mine is for the bedroom ceiling lights. You can confirm this by removing the white plug, put in a new fuse and turn on the bedroom ceiling lights. Chances are the fuse will blow and the sixth small square LED on the top of the Multiplexor will not illuminate. See the photo below. If the fuse does NOT blow and the sixth small LED illuminates, you have a shorted wire between the Multiplexor and the light fixture.

The Multiplexor has a FET (field effect transistor) for each individual output. When the fuse blows with no output load connected (white plug disconnected) it means the FET is shorted. DO NOT buy a new Multiplexor. The FET cost less than $5 and is easily replaced with a soldering iron and needle nose pliers.
Remove all the wires from the Multiplexor and the plastic cover. The bad FET will be the 6th one from the left. Get the number off it and Google it to find an internet source. If you're uncomfortable doing that then call a TV or Computer repair place and see if they'll do it for you.

Good Luck and hope you enjoy your Beaver.

Russ
2006 Monterey Laguna IV

Title: Re: Lights in bedroom out. Circuit issue?
Post by: Lee Welbanks on September 20, 2015, 03:16:16 AM

Russ,

Now that is some great info to log into the memory bank for future use. Easy test and simple fix without R&Ring parts. Hope this will cure his fuse blowing problem.

Title: Re: Lights in bedroom out. Circuit issue?
Post by: Joel Ashley on September 20, 2015, 04:37:10 AM

I'd open the lamp holder and check for a short, but also the wall switch, which on occasion has been reported here as troublesome.  Getting at the switch can be no picnic however, from what I've heard.  And touchpads can be tricky.  But if a wire has inadvertently gone to ground there, it should be easy to see and reroute.   

Appreciate the info, Russ;  I've been learning some circuit board repair myself, for this very reason - it's cheaper to repair myself if it can be done at all, and electronics is our world nowdays.

-Joel

Reference, Load 6, module A:

Title: Re: Lights in bedroom out. Circuit issue?
Post by: Fred Brooks on September 20, 2015, 02:54:08 PM

         Hi Guys,

    Thought I would share a few things with all concerned on how this multiplex system is engineered and fundimentally works. It was designed to eliminate excess wiring and basically daisy chain all the switches thru 3 wires. Each switch has a dedicated "Address". When you depress a switch, The master controller says I know which switch is calling me and tells the multiplexer to execicute that command. You cannot substitute one switch for another and if you send another power source down the wires you will damage the controller. Russ took it to the next level which is correct. However these are pricy components so take caution when working with them.
      I would disconnect the output wire from the multiplexer that goes to the bedroom light and test again. If the fuse blows, the issue is in the multiplexer. If the fuse does not blow then the issue is in the wiring or the light.
       Hope this helps, Fred

Title: Re: Lights in bedroom out. Circuit issue?
Post by: Bert Garnes on November 21, 2015, 09:15:29 PM

Sorry it took so long to get back to everyone.  Thanks for the detailed information.  We figured out the problem it was the back light.  We isolated first the multiplexor, when we removed the cords nothing blew so we started on the lights then and found the back one was the issue.  Since we have only had the coach a little over a year we have slowly been changing out the lights to LED's looks like the bedroom is next  :)

Thanks again