Wiring for Momentary (MOM) Switch 1997 Allegro

[Linda]

Well, we drove our RV home to OK after purchasing it in FL without any trouble.  But, now the fun has begun!  I have been reading a lot about the MOM switch on this website but did not see my exact problem.  I thought it was broken because it kept popping back to center.  We removed it and after going to the local RV for help I learned that was the way it was supposed to work.  Unfortunately, we reinstalled it the way we thought it was originally, but now it does not work. 

This switch has 6 terminals, 2 at the top, 2 at the bottom and one on each side.  White is on 1 side and blue is on the opposite side.  There are 2 green short wires that attach to the top of the switch and the bottom of the switch on each side.  The blue is the hot wire from the converter.  But now it is not working at all. 

Could the switch be messed up or could I have it wired incorrectly?  Is there any way to replace this switch with something simpler?  Thank you for any help you might offer.  Obviously, we do not know what we are doing! 

[DaveVA78Chieftain]

Does this switch have ON-OFF-MOM, MOM-OFF-MOM, or OFF-MOM positions?  OFF would be center.  BTW, MOM stands for Momentary which is why it spings back to OFF when you release it.  Allows you to use the House battery bank to assist in starting the engine when the chassis battery is low on power.

There are several possibilities for this.

Dave

[Linda]

The MOM has the word "ON" above it and "12V" below.  It always goes back to center.  I might be able to read the words on the actual switch or send a photo, if that would help. 

I never heard of a MOM until yesterday, when I took it out and took it to a RV dealer.  He said it might still be good, which is why I tried to reinstall it.  I have a notebook full of information that came with the motorhome but do not see it mentioned.  Did not understand its purpose until reading some of your posts on this web site. 

[Linda]

It is MOM-OFF-MOM

[LJ-TJ]

   
• Not intending to be a smart bum but the first lesson I learned working on my rig was take lots of pictures of what I was working on. I found when I got side tracked on a project I'd for get what went were. Even a year or two later if I was trying to figure something out I could go back and look at what I had done.
• Now I have a Dual/MOM. I'm sure I'll get my wrists slapped for this however this is my understanding of how it works.
• You hop in your rig and it sounds like it's not going to start or the Chassis battery is low. You push the MOM side of the switch. What happens is electrically through a solenoid the House battery is connected to the Chassis battery to give the chassis battery a Jump start just as if you went out side and put a set of jumper cables on the two batteries. My switch is spring loaded so after I let it go it springs back to neutral.
• Now once you got your rig running if you push your switch to Duel what happens is through a solenoid your Chassis battery and House battery are connected to your alternator and allows both your house and chassis battery to be charged while driving down the road. Now here's the trick. When you stop.You MUST put the dual/MOM switch in the neutral position. If you don't and you have any draw on either battery it will draw down both batteries and then you'll really be up a creek with out a paddle because you'll have no batteries at all. Hm?

[Oz]

smart bum...

[Linda]

Wish I had started with the photos yesterday, before trying to work on this MOM.   Just decided to take the "money pit" to the friendly RV man and keep him is business...you gave great advice and I still have today figure out this mess I created.   Please feel free to advise...this is a learn as I go project!!!

[DaveVA78Chieftain]

A picture would be best.  Not exactly sure what you mean by  "There are 2 green short wires that attach to the top of the switch and the bottom of the switch on each side. "  MOM-OFF-MOM implies it energizes the aux start relay from either direction so my initial guess is the green wires are jumpers from top to bottom.

I take it you now understand what this switch is for correct?  Hmm, which brings up the question of how do you know it is not working?   All it does is energize the AUX Start relay which cross connects the chassis and house battery banks.  I have a hunch your rig may have a battery control center (BCC) under the front hood.  If so, then the AUX Start relay is most likely located there.

Dave

[Linda]

Thank you for all your help...I am beginning to see the light!!! 
Linda