What does this blue wire do?

Benhuan · Feb 27, 2020

Hi,
I bought a Radion xr30w pro I’m not sure the gen second hand. The lights work fine but I noticed that the fans don’t turn on. So I opened the light up and it revealed this blue wire isn’t connected to anything. Is that the reason? I can’t seem to find anywhere to plug it.
thanks

dantimdad · Feb 27, 2020

That sends you back out of the matrix.

Retro Reefer · Feb 27, 2020

The blue wire (PWM) on PC fans is typically used to control fan speed with some kind of resister. Not sure if or how it’s applied in these lights.

Jamesrup0411 · Feb 27, 2020

Should post on ecotech sponsor forum they should be able to give you the right answer

Strawberry · Feb 27, 2020

It looks like they’ve modified the wiring. Just search the manufacturer and model number to get more info on whether it can be wired differently for different speed settings// incoming power.

Strawberry · Feb 27, 2020

Typically in DC applications, red (+) and black (-) correspond to the positive and negative incoming voltage. In a lot of applications, blue wires are typically “control” wires and use low voltage among inputs like your temperature sensor so that the controller knows when to actuate (turn on) the fan. It looks like they’ve spliced those two voltage lines together to complete a circuit, possibly because the thermostat wasn’t working correctly to tell the fan when to come on, or just a damaged connector and instead of fixing it they just did it the lazy way.

Strawberry · Feb 27, 2020

If you can, post some more pictures of the board and I’ll see if I can make anything of it. I just repaired my noopsyche the other day after it decided to take a swim!

Sisterlimonpot · Feb 27, 2020

Benhuan said:
Hi,
I bought a Radion xr30w pro I’m not sure the gen second hand. The lights work fine but I noticed that the fans don’t turn on. So I opened the light up and it revealed this blue wire isn’t connected to anything. Is that the reason? I can’t seem to find anywhere to plug it.
thanks

I'm quite certain that isn't an original fan. I've replaced a few of the early generation fans and none of them had 3 wires to the fan only 2.

I suspect that the original owner needed to replace the fan and bought one locally.

I don't think ETM offers those fans anymore, which is probably why you see a 3 wired fan in yours. And if yours isn't working anymore, a fan with the same dimensions will work.

Somewhere in my build thread I detail fan replacement....

Sisterlimonpot · Feb 27, 2020

For some reason I omitted that from the thread transfer, you can view it starting at post 13:

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My rendition of 300 - Reef Central Online Community

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Brew12 · Feb 27, 2020

I doubt that the blue wire is your problem. Fans normally default to maximum speed when the PWM wire is not connected. I would check to see if you have 12VDC at the fan wiring inputs.