fan_header pluged in

[OCD Tweaker]

my computer wont boot because it thinks no is no fan connected to the CPU header

my bios says disable or set the fan speed to low(bios version 3802) asus z170-ar mobo

1)i have my water pump connected to the pump header

2) i have 3 fans plugged into the CPU header using a splitter

3) i also have the board set to tpu-ll (to tell the motherboard i'm water-cooling) CUSTOM LOOP

i have figured out out to get around this by disable the CPU temperature setting, but unfortunately when doing this it also disables my pump speeds to wear my pumps run 100% all the time and it is very LOUD doesn't make very much sense to me

If anybody has any ideas on how to remedy this issue that would be awsome

 

[Paperdoc]

The key question is, what do the instructions for your liquid cooling system tell you to do? Are you supposed to connect the pump and fans that way?

Then there's something odd about the fans. You say three of them are connected together using a Splitter, and that is plugged into the "CPU header". I assume you mean the CPU_FAN header, and not the CPU_OPT one. Now, any Splitter SHOULD connect the speed signal (Pin #3) of ONE of its fans back to the mobo host header, and ignore all the others. Many do this via the pins on the output male connectors - although they are 4-pin systems, only one output connector has all four of those pins; the others all are missing Pin #3. So, if that's how yours is, examine closely. Do you have a fan plugged into the ONLY output connector on the Splitter that has all four pins? Or, is your Splitter of a different style? Some are small boards, for example, with all pins on all headers, and only one of those headers is marked as the important "must use this one" header.

If you have a fan plugged into the correct output of the Splitter and no speed signal is getting back to the CPU_FAN header, try switching around which fan is plugged into which output connector, just in case one fan's speed signal if bad.

 

[Rogue Leader]

my computer wont boot because it thinks no is no fan connected to the CPU header

my bios says disable or set the fan speed to low(bios version 3802) asus z170-ar mobo

1)i have my water pump connected to the pump header

2) i have 3 fans plugged into the CPU header using a splitter

3) i also have the board set to tpu-ll (to tell the motherboard i'm water-cooling) CUSTOM LOOP

i have figured out out to get around this by disable the CPU temperature setting, but unfortunately when doing this it also disables my pump speeds to wear my pumps run 100% all the time and it is very LOUD doesn't make very much sense to me

If anybody has any ideas on how to remedy this issue that would be awsome

One problem you have is plugging 3 fans into 1 header. You should never do more than 2. In fact its possible unplugging that 3rd fan may cure your problem. Try this first

 

[Paperdoc]

Three fans on one header is acceptable IF their total max load is under 1.0 A. So, what fans - maker and exact model numbers - do you have there, so we can check the specs?

 

[OCD Tweaker]

its DIY 4 pin splitter and i have 3 non pwm fans connected to the DIY PWMN 4 pin splitter that is connected to the CPU_fan.

i unplugged the splitter i still have the pump in the right header i still have the same issue

EDIT( the fans that i bought were made in china i bought them off of ebay for 3 bucks they do have a moled connector as well as 3 pin connector thats all i know) these 3 fans are purely for looks

 

[Paperdoc]

OK, have a close look at those cheap fans. You say they each have TWO connectors on the end of their wires, a Molex 4-pin and a female fan connector. First of all, you must ONLY use ONE connector on each fan. Do NOT connect both a Molex and a fan connector to different places.

But my main interest is in how many wires there are from each fan to its connectors. On a standard 3-pin fan, there are 3 wires. Pin #1 is Black (Ground), Pin #2 is Red (+vdc supply, varying for speed control), and Pin #3 is Yellow, carrying the speed signal from the motor back to the mobo header. However, IF those fans were really intended mainly for use with the Molex connection to a PSU output, they may NOT have the Yellow wires to the female fan connector. Without that connection, the mobo header will receive NO speed signal, which could explain your problem.

There is also another possibility IF the Yellow wires are present on all 3 fans. You say you made a DIY Splitter. Did you simply connect all three wires of the same color together from each fan? If you did, that is just right for the Black and Red lines, but NOT for YELLOW! If you send three different speed signals together to a mobo header it cannot read them properly and will get wrong and wildly varying results, causing major confusion. So do what any proper commercial Splitter would do. Connect to the mobo header only ONE fan's yellow wire. Leave the Yellows from the other two fans completely disconnected from anything, but tape up the ends so they don't short to something.

Note also, once you get this to work, that the CPU_FAN header the fans are plugged into will need to be configured to use Voltage Control Mode (aka DC Mode, and NOT PWM Mode, since you are using 3-pin fans.

 

[Paperdoc]

Thanks for Best Solution. Now I'm curious about what you found and whether you were able to get it fixed?