LED, 2 way switch wiring not working

Question

I will give as much information as I can, but my knowledge is limited.

There is a staircase with a 2 way switch. There are 10 LED lights throughout the stairs. They are using direct current.

The old LEDs were taken out and now I have 10 holes with 2 wires each. I GUESS one wire is positive (+) and the other is negative (-).

When I connect ALL of my new LEDs, each postivie to the positive wire in the wall and each negative to the negative wire in the wall, all of them light up extremely low.

After that, I tried to connect them one by one to see what happens.

To do so, I connected all the wires from the wall with each other (1st hole's 2 wires were connected together, 2nd hole's 2 wires were connected together, etc) and in one hole only, I connected my LED (tried the wires to see where it lit up, knowing this way, the positive and negative). The light that came out was bright and as it should be.

So next, I left everything as is, and connected one more LED to another hole. Once I did that, the light was again extremely low as it was when I connected all of them.

Any ideas of what is happening or what I am doing wrong?

The new LEDs are from an LED strip that was cut, and 2 wires were solder, one on the positive and one on the negative.

I am adding a schematic, have in mind I have nothing to do with electrical engineering. Just trying to make it easier to understand what I am talking about.

^{simulate this circuit – Schematic created using CircuitLab}

For further details, if you need something I can check that have not said above, please ask me.

Thank you!

New (transformer/adapter) New LED

Old (transformer/adapter)

Old LED

Answer 1

The original LEDs were driven by a constant-current source and were therefore wired in series.

Your replacement LEDs need to be driven by a constant voltage, and therefore need to be wired in parallel, which is how you bench-tested them.

You're going to have to figure out a way to repurpose the wires inside the wall in order to get the LEDs connected in parallel rather than in series. It may be necessary to pull new wires.

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I found out each hole in the hole has the 2 cables the old LEDs used AND 2 more cables, that were wrapped together. So now I have 4 cables. Each pair, has a positive and a negative. Any idea what I should do?

That's actually good news. It means that you don't need to pull any new wires.

What you likely have is "zip cord" running from hole to hole, wired something like this (original setup):

You just need to reconnect the wires in the holes like this: