[SOLVED] LED lights not working on rear case fan ?

Mar 25, 2022
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Whats up guys, sorry if this topic has been discussed before but I haven't come across a solution yet. I recently installed a new rear case exhaust fan on my PC (enermax D.F. Vegas 120mm) which has LED lights but they're not working for some reason :??:. The lights do briefly light up every time I power on the PC but then turn off and remain that way. I have tried configuring it with aura sync (fan controller software) but no luck. I have read on other forums that I have to adjust and run the fan at the full 12v in the BIOS in order for them to light up; I've tried that but can't find any sort of setting to do so. I'm stuck as to how to get them working, any input will be greatly appreciated. Thanks in advance guys.

Ruben

CPU: AMD Ryzen 3400G w/ Integrated Graphics
Motherboard: Asus X370 Pro
Ram: Samsung 32GB (8GB x 4)
SSD/HDD: Samsung Qvo 1TB SSD
GPU: None
PSU: Enermax Revolution Xt II
Chassis: Enermax Ostrog Gt
OS: Windows 11 x64
Monitor: Asus VE248H 24" Monitor
 

Paperdoc

Polypheme
Ambassador
The likely root of the problem is that the LED's on that fan are simply connected in parallel with the motor so that they get whatever power the motor is fed. When the mobo fan header reduces the fan's speed because your system is running cool, the LED's get reduced Voltage and dim too much. Aeacus' suggestion above is one way to fix this - force the fan to run full speed all the time.

I have four other ideas. First is that I see in the specs that the fan has a small LED Control button somewhere to set its light options. ONE option is to press and hold that button for 3 sec to turn the LED's off. The fan will remember the last LED setting and use that on reboot. Have you set it to the OFF display? It might light briefly at reboot and then turn itself off. If that has happened, a single short press of the button will change to a different LED display pattern.

If that's not the issue, check this detail of header configuration. I presume the fan is plugged into one of the two mobo CHA_FAN headers. See your mobo manual p. 3-8. FIRST, ensure the setting at upper right is PWM, not DC. Then back out of BIOS Setup , SAVE and Exit, and the system will reboot. That MIGHT change this problem. IF the header had been set to DC Mode, the fan SPEED would be under automatic control by reduced Voltage that could cause this issue. BUT if the speed is being controlled by PWM Mode, and that fan's internal wiring is designed a certain way, using PWM Mode may solve your problem.

If that still does not solve it, try this, related to Aeacus' suggestion. In BIOS Setup for that header, select the Manual option at bottom right. Then change the points on the "fan curve" above so that at all lower temperatures the minimum speed is higher that it was before. Back out, SAVE and Exit to reboot. You may have to try this several times to find the right minimum speed. This process can keep your fan running under automatic control rather than fixed full speed, but will not allow the power feed to it to go so low that the LED's do not light up.

And the fourth option is almost the same as Aeacus' suggestion. That was to re-connect the fan differently to force it to full speed all the time. You can accomplish the same thing without re-connection. In BIOS Setup at the bottom of the fan header configuration screen, choose either Full Speed or Turbo (not quite full speed, but fixed pretty fast) so that power to the fan from the header never goes low enough to dim the LED's.
 
Reactions: Ru1984

Aeacus

Champion
Ambassador
Based on fan specs,
link: https://www.enermax.com/en/products/d.f.vegas

It comes with one "1 x 4 pin fan power adaptor". Based on how it is written, i think it is 4-pin -> molex adapter. If so, you can unplug your fan from MoBo, use that adapter, and plug it directly to any molex connector your PSU has. This way, fan will get 100% power but downside is, that it will run 100% at all times, without any speed adjustment.
 
Reactions: Ru1984

Paperdoc

Polypheme
Ambassador
The likely root of the problem is that the LED's on that fan are simply connected in parallel with the motor so that they get whatever power the motor is fed. When the mobo fan header reduces the fan's speed because your system is running cool, the LED's get reduced Voltage and dim too much. Aeacus' suggestion above is one way to fix this - force the fan to run full speed all the time.

I have four other ideas. First is that I see in the specs that the fan has a small LED Control button somewhere to set its light options. ONE option is to press and hold that button for 3 sec to turn the LED's off. The fan will remember the last LED setting and use that on reboot. Have you set it to the OFF display? It might light briefly at reboot and then turn itself off. If that has happened, a single short press of the button will change to a different LED display pattern.

If that's not the issue, check this detail of header configuration. I presume the fan is plugged into one of the two mobo CHA_FAN headers. See your mobo manual p. 3-8. FIRST, ensure the setting at upper right is PWM, not DC. Then back out of BIOS Setup , SAVE and Exit, and the system will reboot. That MIGHT change this problem. IF the header had been set to DC Mode, the fan SPEED would be under automatic control by reduced Voltage that could cause this issue. BUT if the speed is being controlled by PWM Mode, and that fan's internal wiring is designed a certain way, using PWM Mode may solve your problem.

If that still does not solve it, try this, related to Aeacus' suggestion. In BIOS Setup for that header, select the Manual option at bottom right. Then change the points on the "fan curve" above so that at all lower temperatures the minimum speed is higher that it was before. Back out, SAVE and Exit to reboot. You may have to try this several times to find the right minimum speed. This process can keep your fan running under automatic control rather than fixed full speed, but will not allow the power feed to it to go so low that the LED's do not light up.

And the fourth option is almost the same as Aeacus' suggestion. That was to re-connect the fan differently to force it to full speed all the time. You can accomplish the same thing without re-connection. In BIOS Setup at the bottom of the fan header configuration screen, choose either Full Speed or Turbo (not quite full speed, but fixed pretty fast) so that power to the fan from the header never goes low enough to dim the LED's.
 
Reactions: Ru1984
Mar 25, 2022
32
1
45
0
Based on fan specs,
link: https://www.enermax.com/en/products/d.f.vegas

It comes with one "1 x 4 pin fan power adaptor". Based on how it is written, i think it is 4-pin -> molex adapter. If so, you can unplug your fan from MoBo, use that adapter, and plug it directly to any molex connector your PSU has. This way, fan will get 100% power but downside is, that it will run 100% at all times, without any speed adjustment.
I'll try using the molex connector adapter and see what happens, I appreciate the suggestion, thanks!
 

Karadjgne

Titan
Ambassador
Those fans have a mode button, the DF's weren't supposed to be motherboard controlled for led status.

Once the fans are powered up, they'll revert to last known setting. Probably 'off'

The power adapter is for ppl using the optional seperate controller, that also comes with the Enermax RevoBron psu. It has several different speed options, like silent or whisper that run the case fans at a set amount of psu load, so the fans will connect to the controller, connected to the psu, bypassing the motherboard.

Fans and lighting are seperate things.
 
Reactions: Ru1984
Mar 25, 2022
32
1
45
0
The likely root of the problem is that the LED's on that fan are simply connected in parallel with the motor so that they get whatever power the motor is fed. When the mobo fan header reduces the fan's speed because your system is running cool, the LED's get reduced Voltage and dim too much. Aeacus' suggestion above is one way to fix this - force the fan to run full speed all the time.

I have four other ideas. First is that I see in the specs that the fan has a small LED Control button somewhere to set its light options. ONE option is to press and hold that button for 3 sec to turn the LED's off. The fan will remember the last LED setting and use that on reboot. Have you set it to the OFF display? It might light briefly at reboot and then turn itself off. If that has happened, a single short press of the button will change to a different LED display pattern.

If that's not the issue, check this detail of header configuration. I presume the fan is plugged into one of the two mobo CHA_FAN headers. See your mobo manual p. 3-8. FIRST, ensure the setting at upper right is PWM, not DC. Then back out of BIOS Setup , SAVE and Exit, and the system will reboot. That MIGHT change this problem. IF the header had been set to DC Mode, the fan SPEED would be under automatic control by reduced Voltage that could cause this issue. BUT if the speed is being controlled by PWM Mode, and that fan's internal wiring is designed a certain way, using PWM Mode may solve your problem.

If that still does not solve it, try this, related to Aeacus' suggestion. In BIOS Setup for that header, select the Manual option at bottom right. Then change the points on the "fan curve" above so that at all lower temperatures the minimum speed is higher that it was before. Back out, SAVE and Exit to reboot. You may have to try this several times to find the right minimum speed. This process can keep your fan running under automatic control rather than fixed full speed, but will not allow the power feed to it to go so low that the LED's do not light up.

And the fourth option is almost the same as Aeacus' suggestion. That was to re-connect the fan differently to force it to full speed all the time. You can accomplish the same thing without re-connection. In BIOS Setup at the bottom of the fan header configuration screen, choose either Full Speed or Turbo (not quite full speed, but fixed pretty fast) so that power to the fan from the header never goes low enough to dim the LED's.

Before trying Aeacus' method and using the molex adapter, I went ahead and tweaked the setting in the BIOS like suggested. I raised the points on the fan curve to a higher setting and that did the trick. The L.E.D.'s now light up and I am able to change the light pattern with the push-button switch. I really appreciate your guidance, many thanks.

Ruben
 

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