Apologies if I'm using these terms incorrectly.

I'm trying to wire 12V LED lights from a battery. I want to be able to switch on/off the switches at two different sides of the room, and I want a dimmer switch placed next to one of those switches.

I've researched and figured out that I need two SPDT On/On switches wired according to this website, but I don't know where to place a dimmer. Alternatively, is there anywhere that sells a SPDT On/On switch with a dimmer built in?

  • Just use spdt switch saying on/on is confusing because you really are configuring A 3 way switch, I don’t know of a dc 3 way dimmer but that would be off topic anyways. I would see Greg’s answer it would work.
    – Ed Beal
    Commented Nov 5, 2019 at 23:34
  • 1
    Wow, you are into some rather expensive RV stuff. Just so you know, if you swerve over into the LED lighting world, dimmers get a lot more versatile and a lot cheaper. E.G. amazon.com/dp/B012G2D89O They make wireless remotes, there is even kit for doing RGB lighting and controlling that. I have also seen 12V LED dimmers/controllers from major brands of mains-dimmer suppliers, at better prices than the RV market. Of course they fit in standard full size junction boxes. Commented Nov 6, 2019 at 5:09

1 Answer 1


The section or graphic titled 'SPDT ON/ON SWITCHES' near the end of the linked article illustrates exactly the same circuit used for a "3 way" light in a mains-powered home.

If you want the dimming function to happen regardless of which switch is turned on, that's easy. Insert the dimmer in the connection between the battery and first switch, or between the second switch and the lamps.

While technically it would work to let the switches cut the power from the dimmer to the lamps (ie, insert the dimmer between the battery and the switches), it's probably superior to place the dimmer between the switches and the lamps. With it placed here the switches cut the input power to the dimmer. If the dimmer were left always powered as in the first arrangement then it would consume some energy even when the lamps are disconnected. That's not ideal in a battery-operated context.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.