Dimmer switch

[katkandu]

Help.. I’ve purchased a 12V high side dimmer switch for some of my led cabin lights. When I removed the old toggle switch from the wall, there is 2 red wires. The new dimmer switch has 3 wires !! Red white and black. Can I make this work somehow? 🤔

[rudykruger]

There has to be a ground wire running near your existing switch as well. If you dig a little you should find a (probably) black wire in there as well.

One of your existing reds come from the +12V source, the other goes to the lights. Use a multimeter to figure out which of the two reds have +12V on it. Connect this HOT wire to the red wire on your dimmer switch.

Connect the white wire of the dimmer to the other red wire that came from your original switch (the one that goes to the lights).

Finally connect Black to the ground wire that you dig out. You probably have to splice it in. If you cannot find a ground wire near the switch, run a section of ground wire from the nearest light to the switch.

[Wotname]

Originally Posted by katkandu

Help.. I’ve purchased a 12V high side dimmer switch for some of my led cabin lights. When I removed the old toggle switch from the wall, there is 2 red wires. The new dimmer switch has 3 wires !! Red white and black. Can I make this work somehow? 🤔

In addition to rudyk's good advice, did you check to see if the dimmer is suitable for your LED lights. Some dimmers are suitable, some aren't.

[katkandu]

I looked around, no ground wire I can see. I suspect it’s not there because these lights are also able to be shut off with a breaker switch on my 12v panel.

[katkandu]

When I purchased it, it said it was for led lights and others said make sure it’s a high side dimmer. Don’t know what that means but it is lol.

[katkandu]

Something else I probably should mention. These puck lights were originally mini halogen bulbs that I converted to led disks

[Wotname]

Originally Posted by katkandu

When I purchased it, it said it was for led lights and others said make sure it’s a high side dimmer. Don’t know what that means but it is lol.

Should be OK then

[Wotname]

Originally Posted by katkandu

I looked around, no ground wire I can see. I suspect it’s not there because these lights are also able to be shut off with a breaker switch on my 12v panel.

Ahh.... no, your suspicions are incorrect!

There might not be negative (ground) wire near the switch but there will be one at the LED light fixture itself.

But it doesn't really matter much where you find a negative, any one of them will will work.

To recap rudyk's advice - the dimer needs a positive source and a negative return (the red and black wires) before it will operate. The output of the dimmer (white) needs to go directly to the LED positive side. The other side of the LED will be the negative return going back to the negative (ground bus).

[katkandu]

Originally Posted by rudykruger

There has to be a ground wire running near your existing switch as well. If you dig a little you should find a (probably) black wire in there as well.

One of your existing reds come from the +12 in V source, the other goes to the lights. Use a multimeter to figure out which of the two reds have +12V on it. Connect this HOT wire to the red wire on your dimmer switch.

Connect the white wire of the dimmer to the other red wire that came from your original switch (the one that goes to the lights).

Finally connect Black to the ground wire that you dig out. You probably have to splice it in. If you cannot find a ground wire near the switch, run a section of ground wire from the nearest light to the switch.

. Thank you 🙏🏽

[katkandu]

Thank you ����

[YANDINA]

LED (and incandescent lamp) dimmers work by turning on and off rapidly with the on time percentage adjustable. This requires 12 volts to operate, hence the need for the ground wire.

During the OFF portion of the cycle there is 12 volts across the dimmer. We have a prototype of a 2 wire dimmer that has never been put in production. It works by charging a capacitor during the OFF time to keep it running during the ON time. It also has a daylight sensor to act as an automatic anchor light switch. Perhaps we should take another look at it?