1 fan out of 2 running

[VVBondie]

Hi !

Yesterday, I realized my fans were a bit louder than previously so I opened the laptop and cleaned them. I started the computer without backplate to see if everything was fine and realized only 1 fan was actually working.

I tested at low temperature and high temperature and only one is working  in any case (see picture).

I went to the BIOS and saw that the "fan always on" was actually enabled by default. So I disabled it for the sake of the test. Both fans did not turn on at any point after that (including at high temperature). I enabled anew the "fan always on" option in the BIOS. I then visually confirmed that both fans were spinning while I was looking at the BIOS.

I downloaded HP CoolSense with no effect.

SpeedFan software confirmed only one of the fan was spinning. As the motherboard is not compatible, I could not adjust the fanspeed.

Finally, it seems that the fans are well connected to the motherboards:

- when i unplug the fan not spinning, I obtain a cooling fan 90B error on boot,

- when i unplug the fan which spins, I obtain a cooling fan 90B error on boot,

- during boot (which is extremely fast on my nvme ssd), both fans spin,

- when turning off, briefly before the computer turns off, both fans spin.

Any idea ? I believe having both fans on may help in managing temperature (and noise) when I'm using the GPU intensively.
Edit : picture link https://imgur.com/a/dNXzjBk

[Huffer]

Speedfan commonly detects only one fan spinning fast enough to seem to do any good. That is normal. If you can see both fans spinning then odds are you are OK. Are you getting a temperature readout on speedfan? The fact that disconnecting fans gives a 90B error tends to show the motherboard is OK. 

[VVBondie]

Thanks for your fast answer !

I'm sorry, I think I was not clear. Both fans are spinning only in BIOS and at launch. As soon as windows is booted, only one fan is on. I have look at it, both with my eyes and with speedfan.

I agree with you there is no hardware at fault here, the motherboard is connected to both fans, both speed can be read and both fans can spin.

Having only one fan spinning results in higher termals. I believe that could reduce the lifetime of my fan, my gpu and my cpu.
Still, thermals are in check most of the time (I managed to obtain 71°C in the GPU and 74°C in the CPU after 10 minutes of heavy load, don't really want to go higher than that).

My question was more like, do we agree that the second fan should be spinning when the first one is spinning at 4800 rpm ? Does HP configured the fan speed like that ? Do you know any way to change that ?
The laptop is still in warranty for 2 months, so I am thinking of sending it in for repair, but maybe there is nothing to be done here.

[Huffer · Accepted solution]

We have had lots of folks point out the second fan rarely if ever spins. Your temps in the 70s are well within limits. You can try sending it in but I am not sure HP would even recognize a defect to be serviced. 

[VVBondie]

Thanks, that the information I was looking for: it's like that by design. I am not saying I understand why but you are right, most of the time the thermals are ok.

[Huffer]

You also did not see me say I understand, either. Just reporting the reactions of others and my own experience with the HP laptops I have owned. I had a Spectre 13-vxxx on which the second fan never really kicked in. Its about 3 years old now and still going strong, running cool. 

[Joshua781227]

Hello @Huffer . my laptop issues an error of Fan 90b error and checked my RPM of my first fan 2100+ and second is only 200 . i tried updating bios, clean, reset etc. but still the error is so persistent. i want to remove the error and return the normal speed of my fan 2. please help. my laptop is still 1 year 1 month old