OK so I came across this forum a back while looking for an answer to this question and found some excellent advise that I would like some additional info for.

I have purchased the above server in a 1u case however it's far to noisy for its location, (I know it's the burden of a server using passive cooling). So I have moved the motherboard into a 4u case and hoping to use active cooling, using 2 pwm fans using an official hp splitter with a 4 pin adaptation.

Now this server needs all 6 fan headers connected to the board to boot and making those connectors is fine, however 12 fans in a pc that won't really require them for airflow due to the new 4u case and the active cooling on the heatsinks.

My question is can I connect the wires together to make 1 single 4 pin pwm connector as 1 sensor wire is for input and the other is output as the fans from the server are back to back running 8k rpm each or will I have to have all 12 fans.

Happy to give more information if required I tried to add photos but I needed more rep to post.


An option, though definitely not exactly what you would call "proper" is to create a splitter with the yellow line split between multiple male connectors that then connect to the motherboard headers. A crude diagram is below:

|--- <yellow line only> -- <motherboard accessory fan header 0> | FAN ---|--- <passthrough red, black, yellow, and PWM> -- <motherboard CPU Fan header> | |--- <yellow line only> --<motherboard accessory fan header 1>

The yellow line is the sense wire and is used to detect the frequency of the fan rotation. By splitting this between the multiple headers, they will all detect the fan's rotational velocity, and thus allow your server to boot.

Now the other question is, even though you can do this, should you? It may be better to just snag some very quiet fans instead - which would be much easier to find since the case is now 4U.

  • Would love to however hp have made a 6 pin connector for the fan headers so they are not standard and I cannot find 6 pin fans to connect to them if you can find them I would be happy to use them. I am curious though as to what the issues faking the fans will cause proving everything stays in working temp, also here is the official fan connector that was advised by hp themselves i.ebayimg.com/images/g/wJ4AAOSwPgxVNekS/s-l300.jpg – Steven Williams Nov 22 '16 at 23:37
  • Ah - that's a good point. A bit of Googling ran into this: silentpcreview.com/article1377-page9.html. To distill it quickly, HP only detects if there's a trickle voltage, not an actual frequency: You can trick the Microserver into "seeing" an ordinary 4-pin PWM fan by connecting the Rotation Detect/Tachometer pin to the ground, and SHORT CIRCUIT THE GROUND pins from the fan connector. silentpcreview.com/article1377-page9.html – Brennen Smith Nov 23 '16 at 4:12
  • I have seen that before and looking at it might be ok but since looking at the dl160 vs the dl180 (of which that is for) the pins for the fans on the dl180 are not all used however they are for the dl160 which I have only just seen. See link for the fans for the dl160 ebay.co.uk/itm/… – Steven Williams Nov 23 '16 at 11:42
  • and here is the fan for the dl180 ebay.co.uk/itm/519199-001-DL180-G6-FAN-ASSEMBLY-NEW-/… now would I be right to assume that the hp fan splitter which is meant to run duplex fans that hp advised me to get for the dl160 should work even though its for the dl180 if so that pin out would work and exactly what I was looking for thank you – Steven Williams Nov 23 '16 at 11:44
  • @StevenWilliams Were you able to find a solution? I am trying to do the same and I'm driving myself crazy.... I've tried all combinations and nothing.... – Dryadwoods Oct 6 '17 at 18:23

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