Hp Zbook 15 G2 fan running when off

I was wondering if anyone here could help me, I replaced the motherboard in my laptop with one I ordered from China, for some reason when the laptop is turned off the power light shuts off but the WiFi and sound icons stay lit and the fan runs at 100% speed. When turned on the laptop runs normally with no issues fan control is normal.

The fan runs until the battery or charger are unplugged. There are no other lights when laptop is turned off which makes the issue seem so strange.

 

I just started having this exact same problem with a Zbook 15 G2. I replace the keyboard a few months ago, but everything else is OEM as far as I know. I will let you know after it comes in. I tried re-positioning the power button ribbon cable, and have also applied the latest BIOS and Intel Management Engine driver and firmware. I'm suspicious of the the battery, so I'm ordering a new one to see if that does anything.

 

I thought it was the Intel ME firmware but it turns out the power ic chip is faulty and is shorting out somewhere when off. Makes a bit of sense, maybe the 5v rail for the laptop is permanently on, I can check this hunch by checking the usb ports too.
My guess is that the 5v rail becomes stable again when the laptop turns on, must be some mechanism in place to sort out the shorting issue, I can tell you that you can replace everything but the motherboard is at fault and it seems nothing is changing it.

I returned that dodgy chinese crap and have bought another one from a local supplier, motherboard is only £50 ~ $65 anyway!