Wiring into existing dash switch

Discussion in 'Electrical Stuff' started by farwellbooth, Mar 5, 2015.

  1. farwellbooth

    farwellbooth Member

    Sep 16, 2014
    Seattle, WA
    2010 Sundeck 220
    Merc 350 w/ Bravo 3
    I'd like to wire an led light bar into an existing dash switch. The switch is labelled 'accessory' and nothing comes on when the switch is turned on. There is wiring to the switch and I assume the hot end is somewhere in the boat. Where would this be? It's a 2010 Sundeck, 22 foot. I've also attached a pic of some of the switches. Assuming I can't find the hot end of the accessory wiring, how can I tap into the switch? I could use a volt meter and figure out which post is hot when on and plug my new connection into that. Per the ground, according to the pic and wiring schematics they are all pigtailed together and then ran to the fuse panel ground. I could connect the ground to the switch or the fuse panel ground correct, or does it need to go to the switch. I don't want to cut any wires and I will label anything I take off/unplug. Thanks for the help.

    It's also extremely difficult in getting to the backs of the switches. The bolts to remove the switch panel are also difficult to get to because tons or wiring is in front of them. Any easier way of getting to the backs of the switches for wiring?

    Thank you

    Searay switches.jpg
  2. Hifirush

    Hifirush Member

    Mar 21, 2014
    North Padre Island
    1998 330 DA, 7.4 MPI with V-Drives, raw water cooled, Westerbeke
    twin 7.4 MPI’s with V-Drives
    I don’t have an answer for you, but I like the picture of the boat at the dock! Like the lights and the Christmas Tree!!!

  3. sibnai1

    sibnai1 Member

    Jul 18, 2014
    NJ, USA
    195 Bow Rider 5 Series
    4.3litre V6 I/O Alpha I Gen II
    I did it with my new bilge pump, the original (non functioning) bilge pump was mounted so far back towards the transom and under the engine that I could not get to the wiring or the pump to remove it, so I used a continuity light to see which of the posts on the original bilge pump switch was powered on when the switch was engaged and drew the power for the new pump from it. I grounded the new pump very close to the pump. The side benefit of doing it this way (using the original switches) is that the original fuse for the original bilge pump was naturally incorporated into the new circuit (as tested by pulling the fuse and engaging the switch).

    Probably over-kill but I also wired a fuse right after the switch just incase.
    Last edited: Mar 5, 2015
  4. BillK2632

    BillK2632 Well-Known Member SILVER Sponsor

    Jun 25, 2009
    Lake Norman, NC
    1999 185 Bowrider,
    Mercruiser 4.3, Alpha I
    That Accessory switch should be wired to the fuse panel, there is also a ground bus that all of the swtiches ground to. I would expect all of this is behind the dash in your boat. Hooking your lights up should be a simple as running the + for the lights from the switch (there should be 3 prongs, ground, off, on) The - and + (hot) are already wired, so hook your lights + to the open one, then run the - for your lights to the ground bus.

    I added a switch to my 185 for some interior lights, I just used an open slot on the fuse panel and connected to the common ground. Did the same thing for a 12v outlet. This way everything you add is fused and nice and clean.
  5. BryanOnTheBay

    BryanOnTheBay Member

    Oct 6, 2013
    Edgewater, MD
    "Havana Crush" - 1998 270 Sundancer
    7.4L Mercruiser MPI Bravo III Outdrive
    Do you have your owner's manual? If not, you can download I'd from SeaRay.com. There are some wiring diagrams in there, that show where things connect. Not everything, but a fair amount of the connections.


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