Going from 2 to 3 wire light switch?

[SeventyGTX]

I ordered a light switch with dimmer for the living room/hallway. The current switch has two black wires going to it. I found two wires behind the switch one black and one red I assume are 12v positive and negative. My question is, are both these black wires coming from the lights, or is one ground. Being a wiring dummy, I'm confused as heck on how to wire the new switch up. The new switch has black, red and white wires. I attached a pic of the current switch. Any help is GREATLY appreciated!

[Jagiven]

Those extra wires are probably for an option you do not have. Best to contact Jayco with your vin number and ask for the wiring diagram. All the wires are color coded.

As for the two black wires at the switch. One is hot, all the time, and the other goes to your lights. A multi meter, can tell you exactly which wire is hot. My guess, center wire, but with two wires it will work either way.

[SeventyGTX]

Originally Posted by Jagiven

Those extra wires are probably for an option you do not have. Best to contact Jayco with your vin number and ask for the wiring diagram. All the wires are color coded.

As for the two black wires at the switch. One is hot, all the time, and the other goes to your lights. A multi meter, can tell you exactly which wire is hot. My guess, center wire, but with two wires it will work either way.

Thanks for the advice. I called Jayco before I installed had a 2nd AC and the guy gave me bad info on that, so I'm a bit skeptical to call them. What sucks is the red wire had a small tag on it when I pulled it through. But it fell off into down the hole into the wall so I never saw what it said. Maybe those wires are for solar prep since the sticker is in the hallway just a couple feet away.

[triplebvalp]

Originally Posted by SeventyGTX

Thanks for the advice. I called Jayco before I installed had a 2nd AC and the guy gave me bad info on that, so I'm a bit skeptical to call them. What sucks is the red wire had a small tag on it when I pulled it through. But it fell off into down the hole into the wall so I never saw what it said. Maybe those wires are for solar prep since the sticker is in the hallway just a couple feet away.

Just a couple of guesses here. The red and black wires are for the solar prep. They seem rather large for "other" functions.

The 3 wire dimmer switch will need 12v power to switch, power to lights, and a chassis ground.

[curver900]

why would you go to three wire? the only time three wires come into play is if you are using two switches to control one set of lights or as they say a three way switch. If you are just installing a new switch with a dimmer just change out the two black wires to the new switch using the vm to know which one is hot and which one goes to the light as stated before.



Good luck.

[Vicr]

I'm an electrician and have installed dimmers all over my '16 Precept with LED lights. You need to have a dedicated negative going from the LED dimmer switch to the LED's to be dimmed. Most RV's are wired where there is a common negative going to all the lights on that circuit. You probably will have to fish a dedicated negative wire going to the lights to be dimmed and connect only to the lights to be dimmed. If there is a negative wire going past the last fixture you'll have to connect the negative source ahead of the switch all the way past the lights to be dimmed an to the negative wire going to other lights on that 12v circuit. It's a pain in the a_ _ but look at the wiring diagram on the dimmer switch and it will make sense.

[SeventyGTX]

Originally Posted by curver900

why would you go to three wire? the only time three wires come into play is if you are using two switches to control one set of lights or as they say a three way switch. If you are just installing a new switch with a dimmer just change out the two black wires to the new switch using the vm to know which one is hot and which one goes to the light as stated before.



Good luck.

I asked the seller what the difference in 2 and 3 wire is, and he said it is better to have 3 wire with multiple lights. Our living room and hallway are on that switch and have 8 LED's. That is why I ordered a 3 wire.

[SeventyGTX]

Originally Posted by Vicr

I'm an electrician and have installed dimmers all over my '16 Precept with LED lights. You need to have a dedicated negative going from the LED dimmer switch to the LED's to be dimmed. Most RV's are wired where there is a common negative going to all the lights on that circuit. You probably will have to fish a dedicated negative wire going to the lights to be dimmed and connect only to the lights to be dimmed. If there is a negative wire going past the last fixture you'll have to connect the negative source ahead of the switch all the way past the lights to be dimmed an to the negative wire going to other lights on that 12v circuit. It's a pain in the a_ _ but look at the wiring diagram on the dimmer switch and it will make sense.

Fortunately the main switch panel is just above the switch I am replacing and there are a bunch of wires going to it I can see in the hole. Finding a ground shouldn't be too hard. I hope. Below is the wiring on the switch. One of the black wires going to the current switch is 12v+. Can I use that to connect to the positive side (red wire) of the new switch? Then I would just have to find a ground.

[Vicr]

Originally Posted by SeventyGTX

Fortunately the main switch panel is just above the switch I am replacing and there are a bunch of wires going to it I can see in the hole. Finding a ground shouldn't be too hard. I hope. Below is the wiring on the switch. One of the black wires going to the current switch is 12v+. Can I use that to connect to the positive side (red wire) of the new switch? YES Then I would just have to find a ground.

There is a problem with this wiring diagram. It only shows one wire going to the LED fixture. It's missing the negative wire coming from the dimmer. The negative wire is used in the dimming circuit coming from the dimmer.

[SeventyGTX]

Originally Posted by Vicr

There is a problem with this wiring diagram. It only shows one wire going to the LED fixture. It's missing the negative wire coming from the dimmer. The negative wire is used in the dimming circuit coming from the dimmer.

Here is the back of the switch...

[Jay2504]

SeventyGTX, what the other people are saying is that most PMW dimmers requires a hot and a ground wire going through the dimmer switch and then on to the light to be dimmed. This dimmer may or may not need that kind of connection. Find the +12 side of the old switch and hook it to the red wire of the new switch. Then hook up the other wire from the old switch to the white wire of the new switch. Run a temporary ground to the black wire of the new switch and see if it works. It is possible that it might work. I would not hook it up permanently until you try it. Please tell us what happened. Jay

[SeventyGTX]

Originally Posted by Jay2504

SeventyGTX, what the other people are saying is that most PMW dimmers requires a hot and a ground wire going through the dimmer switch and then on to the light to be dimmed. This dimmer may or may not need that kind of connection. Find the +12 side of the old switch and hook it to the red wire of the new switch. Then hook up the other wire from the old switch to the white wire of the new switch. Run a temporary ground to the black wire of the new switch and see if it works. It is possible that it might work. I would not hook it up permanently until you try it. Please tell us what happened. Jay

Thanks Jay, that's the plan. It is supposed to be here in two days.

[Vicr]