340SDA Split Wiring for forward V-Berth Reading lights and Closet Lights

KevinC

Well-Known Member
Feb 25, 2011
3,813
Long Island, NY
Boat Info
2004 340 Sundancer
Engines
Twin 8.1 V-drives
Recently we had a discussion on the 2003.5-2008 340 Sundancer (SDA) forum regarding the forward lights. Our boats were wired up with a switch forward of the starboard closet to control these lights. Unfortunately on my boat (and apparently others) this switch controlled both the reading lights on the forward bulkhead as well as those atop the closets. We discussed that it would be nice to be able to just have the reading lights on at night without the closet lights but based on how things were wired this is not possible.

After reviewing the owners manual wiring diagrams I noted that it looked like the forward reading lights should have been bridged to the power supplies on the blue/red feed:
0 - Wiring Diagram.jpg

However it was not wired that way. This is what I have (both lights bridged and switched on a single pole):
1 - Original Wiring.jpg
 
While I could have simply bridged the power to the forward lights and allowed them to be controlled by their individual switches I decided to take a different approach. I wanted to be able to turn both on or just leave the forward lights on to be controlled by their switch.

To do this I used a DPDT (Double Pole - Double Throw) Carling Switch to replace the SPST (Single Pole - Single Throw) Switch.

To do this I first had to remove the old switch and bridge the power to both sides of the new switch (each side operates like its own switch - this is the double throw function)

2 - Power to both sides.jpg
 
Then I split the connected wires and added a terminal to the closet lights branch and connected it to one side of the switch (the top and bottom terminal at the two poles for the up and down switch function).

3 - Power to Closet Lights.jpg
 
Then I created a jumper from the reading lights so that I could attach it to both the up and down controls. To do this I took a short loop of wire and added a terminal to it. Then this small loop was joined with the wire controlling the reading lights and I connected them in another terminal. These terminal were connect to both the top and the bottom of the switch. This will allow the reading lights to be on in either switch position.

4 - Power to Forward Reading Lights.jpg
 
Then I tested and reassembled the switch and the panel and screwed back into the wall. Now I can have both sets of lights on:
6 - Forward and Closet Lights.jpg
... or just the forward:

5 - Forward Lights Only.jpg
 
So, if you noticed there was one more connection on a separate row on the switch. This is the connection for the LED switch ground. If I want to have this switch lighted I would simple need to connect that to the boats grounding block.

Thanks for reading and let me know if you have any questions... I hope this helps someone down the road.

-Kevin
 
Thanks kevin, great write-up as usual. Do you have a link to the switch you bought? Were you able to use you original switch actuator?

Thanks again,
Brian
 
Thanks kevin, great write-up as usual. Do you have a link to the switch you bought? Were you able to use you original switch actuator?

Thanks again,
Brian

I used the Blue Sea Systems Contura Switch DPDT Black. Switch positions are: ON-OFF-ON. Part number 8286
This is a complete Carling Switch and Cover with two LED lights - typically used for nav/anchor wiring on a panel.
I picked this up on Ebay for under $20 delivered.

Any DPDT switch should work with this note: It should spec ON-OFF-ON if it specs (ON)-OFF-(ON) then it is a momentary in the on positions. The parenthesis indicate the momentary connection. If it specs ON-ON then there is no OFF position and can work but I wanted the ability to turn off the lights without climbing back up on the bed.

-Kevin
 
One more note on this project: to bridge the two wires in the female spade terminal ends you may need a larger guage terminal for those since there is potentially twice the wire. I used a 16g for the jump and the factory wiring was larger and the schematic spec'd 14g. A 12g-10g terminal should work find (I did twist mine real tight to get it into a 14-16g terminal)

-Kevin
 
I used this one from FP: It has a jumper already on it so no need to make jump wire for power in.

VJDJ-1Carling ON/OFF/ON double pole rocker switch with jumper and two lamps
 
Last edited:
I used this one from FP: It has a jumper already on it so no need to make jump wire for power in.

VM4J-1 Carling OFF/ON/(ON) double pole rocker switch w/jumper no lamps - Ignition switch , SR part# 670521 old #647974 VM4J-1

Ok, how did you wire in the momentary position of the second throw to work the separate lights? Once you let go the lights are off.

-Kevin
 
:oops: Sorry Kevin - my bad - posted wrong switch as I ordered one of the VM4J as well. It is the VJDJ-1Carling ON/OFF/ON double pole rocker switch with jumper and two lamps that I am using for the reading lights.

Thanks for catching that - I edited my OP.
 
:oops: Sorry Kevin - my bad - posted wrong switch as I ordered one of the VM4J as well. It is the VJDJ-1Carling ON/OFF/ON double pole rocker switch with jumper and two lamps that I am using for the reading lights.

Thanks for catching that - I edited my OP.

No problem. I just did not want someone getting confused.

-Kevin
 
Kevin, Can you confirm for the electrically challenged, that the easier fix you mention at the start is to separate the reading lights wire from the closet lights wire, and rejoin the reading lights wire to the hot wire on the other switch post. Thanks for this really helpful write up!
 
MacB. That's right. That was the first suggestion that I had found. But Kevin's dual post is a much better solution. I am changing over to his so as not to have too climb up on bed every time want lights on or off.
 
Yep, you could simply move one wire to the positive. You will still need to cut wire and crimp unless you cheat with one of those scotchlok crimp connections (which I would not recommend for long term use on a boat).

The problem is the two light sets were crimped into one terminal so you need to separate them.

-Kevin
 
Great. Thanks!
 
I added a separate switch to my 320 for the reasons described. Couldn't turn everything thing off without killing the master at the steps.
20180909_103851.jpg
 
Yep, you could simply move one wire to the positive. You will still need to cut wire and crimp unless you cheat with one of those scotchlok crimp connections (which I would not recommend for long term use on a boat).

The problem is the two light sets were crimped into one terminal so you need to separate them.

-Kevin

schotchlok connectors should be banned for use on anything anywhere!!!
 

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