Mystery Switch?

Discussion in 'General Discussion' started by gwhiznel, Dec 1, 2019 at 8:20 PM.

  1. gwhiznel

    gwhiznel New Member

    2
    Nov 28, 2019
    Charleston, SC
    Sundancer 320
    Mercruiser 350 Horizon 5.7 V drives
    Can anyone tell me what this switch is for (the one on top)? It's on my 2004 Sundancer 320, and not covered in the Owners Manual. image1.jpeg
     
  2. BillK2632

    BillK2632 Well-Known Member GOLD Sponsor

    Jun 25, 2009
    Lake Norman, NC
    1999 185 Bowrider,
    Mercruiser 4.3, Alpha I
    I think that is the freshwater pump.
     
  3. Groucho

    Groucho Well-Known Member

    Jun 11, 2008
    Albany/Lake George NY
    2004 320 DA
    6.2 V-Drives
    As I remember the switch for the freshwater pump is down below on the elect. panel. The couple times I used the boat before it was put away I just turned them all on. I was thinking it was for underwater lights....although mine doesn't have them...
     
  4. Lazy Daze

    Lazy Daze Well-Known Member TECHNICAL Contributor GOLD Sponsor

    Apr 21, 2009
    PA
    Various
    Various
    This is one of those questions that comes up at least a few times a year. As noted...

    -- Yes, it is the standard sign for the fresh water pump.
    -- But, depending on the boat that the panel is used in, it may not be used as the actual "switch" for the fresh water system could be on the MDP in the cabin.
     
    Blueone likes this.
  5. gwhiznel

    gwhiznel New Member

    2
    Nov 28, 2019
    Charleston, SC
    Sundancer 320
    Mercruiser 350 Horizon 5.7 V drives
    Thanks! The image looks like a tank with water in it, and arrows indicating flow activation. It really does not appear to be functioning. The fresh water pump switch is on the cabin main distribution panel, and the water pump does come on when activated. I've been told the ACC switches can be used for auxiliary lighting.
     
  6. Lazy Daze

    Lazy Daze Well-Known Member TECHNICAL Contributor GOLD Sponsor

    Apr 21, 2009
    PA
    Various
    Various
    If that accessory switch is not currently controlling anything (either an option you don't have or similar to the fresh water system - just not used on your boat), then, yes, you can use it for something else. The wiring to the breaker/fuse box is already done.

    The same goes for that fresh water system button - it could be used for something else, as well.
     
  7. Henry Boyd

    Henry Boyd Well-Known Member GOLD Sponsor

    Apr 24, 2007
    Newburyport, on the peaceful and serene Merrimack
    ‘09 Sabre 38 Hardtop Express “Serenity”
    Volvo D6 w/IPS450 Pods
    As an addendum to what Dennis posted; If you look in the model specific section of your owner's manual you will find detailed wiring diagrams that will allow you to match up the specific wire color codes. They will also show the pin out location for the switch and breaker on the wiring harness plug on the EIM that controls the switch. That allows you to go to the EIM and locate the unused wire for the switch. This wire is the power (+) side that can be extended to the new device you wish to add and then from that device you just need to complete the circuit to ground(-). On the EIM the switch will have a breaker that will be marked with its capacity. If your device is below the rating of the breaker you need to add an inline fuse equal to the device limit on the positive leg. Obviously, if the draw of the new device is greater than the EIM breaker you either need to find another circuit, or evaluate if the device can be used because it will not draw its max except under unusual conditions.

    H
     
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  8. ZZ13

    ZZ13 Well-Known Member

    Nov 25, 2009
    Lady's Island, SC
    2001 400 Sedan Bridge
    Cummins 450 Diamond
    Seems like it comes up once a week....
     
  9. Korkie

    Korkie Active Member GOLD Sponsor

    616
    Feb 2, 2016
    Leonardtown, MD Potomac River / Chesapeake Bay
    340 Sundancer 2006, Garmin 7612, xHD Radome
    Merc 496 Mags
    Bravo III Drives
    +1 on ZZ13 - I had the same question when I got my 340. :D Honest Question as hard to search for a photo of it.
     
  10. Great Lakes

    Great Lakes Well-Known Member GOLD Sponsor

    588
    Oct 11, 2016
    Lake St. Clair - Michigan (MacRay Harbor)
    2005 390 Sundancer
    GHS Platform
    Bow/Stern Thrusters
    8.1
    I believe the 280 has the same panel and uses this switch. On the 320 and 340 it’s just along for the ride.
     
  11. Korkie

    Korkie Active Member GOLD Sponsor

    616
    Feb 2, 2016
    Leonardtown, MD Potomac River / Chesapeake Bay
    340 Sundancer 2006, Garmin 7612, xHD Radome
    Merc 496 Mags
    Bravo III Drives
    If you read above it is actually very usable.
     

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