Question Case fan issue.

Apr 13, 2021
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My case fans are powered by a molex connector, 4 pin. The case came with an adapter limiting the pins that connect to the fans. I lost the adapter and I reassembled the molex straight from the psu in every combination for the pins possible. I even removed some and tried it, fans still didnt work. Fans spin but dont light up
 

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On a standard female (with 4 holes) Molex power output connector from a PSU there are TWO power supplies. The two Black wires in the middle are both Ground. The YELLOW wire on one end is the +12 VDC supply used to power fan motors. The RED wire on the other end is the +5 VDC source used for several possible things, but ARGB LIGHTS usually require that voltage. I don't know details of the fans in that case. They may have a non-standard connector so that ONE cable in each fan connects BOTH power supply lines to the correct parts of each fan. Now, I suspect strongly that there is a small switch or control board in the case, and all of the fans connect to that. Then there is a cable from that for you to plug into a PSU Molex output for power to that board. I note that the case instructions indicate there is also a way (maybe a set of two pins on that board) for you to plug in the normal cable from your case's RESET button, INSTEAD of plugging that cable into the mobo Front Panel header. It is THAT connection that allows you to use the front panel RESET button to change the light display, or to turn them off completely. It is NOT used as a mobo Reset button. Without that connection made to that little board you have NO control of lights.


I appears you have managed to get the 12 VDC supply to the MOTORS working, but the 5 VDC supply to the LIGHTS is not. That has four possible reasons.

(a) That "adapter" you mentioned is the control board, and you have lost it. You would need a replacement from the case maker.
(b) You do not have the 5 VDC power and Ground lines connected to the little control board correctly, so there's no power available for the lights.
(c) You do not have the cable from your RESET switch plugged into the little board, so you have no way to control the lights or turn them on.
(d) In all the trial wiring you did, you managed to feed 12 VDC into the 5 VDC lights and burn them all out, so they may never work.

Trace down the connections to that fan control board IF you have it and verify whether they all are right. Can you tell if the 5 VDC lines from a Molex PSU output are connected to that board? Is the RESET front-panel button cable connected to that board?
 

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