Fan Splitter Only Runs One Fan

[Mr_Boberto]

Im using a Asus Maxsimus Hero VI Motherboard and just got some new case fans along with a few 3pin Y splitters to make them all work. I plugged them all in the right way and when i boot up only 1 fan spins that i have on the splitter and not both. I attached them to a molex plug and to the power supply directly and still only one ran. Any clue why both fans wont run with the splitter? Im using Purex Pc Fan power splitter cables and 1 set of fans are 2 Cougar 140mm vortex hdb and the other are 2 Corsair 120mm fans

 

[volcanoscout]

Is it only one splitter that this happens on? If you switch the fans around on the splitter, does the same fan not work on the other connector or is it only the fan on a specific connector that doesn't work?

 

[Mr_Boberto]

I tried all 3 splitters I got and each one only operated one fan. I switched the fans connectors around and it operates the other fan that didn't work before but now the one that did work doesn't. I'm assuming I just got shitty splitters?

 

[volcanoscout]

I just looked at the product picture again and noticed that not only do the fan-side connectors have 3-pin molex connectors, they each have tachometer wires running to the same pin in the mobo-side connector. That shouldn't have made any difference when you plugged them into the PSU (both fans should have gone to max RPM), but feeding two RPM reports to the same mobo fan header can have weird results (or no results).

Try disconnecting the tach wire (yellow) from one of the fan-side connectors by removing the pin, then plug two fans into the mobo header again. If the result is still just one fan working, reinsert the pin and return them to the store.

If you have access to a different brand and/or model of splitter, you can try that first and see if the same thing happens, but I think the splitters are the problem.