Workaround for Missing Temp Headers on Z490 Aqua?

Hi,

I've ordered the Aqua Z490; however, there are no temperature headers?! It seems this is common on ASRock, my last 4 boards were Asus.

Thing is, I want to do a custom loop, and there is no direct way of reading the water temperature. Another post talked about using an Arduino Uno to send the data to the board via RS232. AFAIK the z490 Aqua has no a coms port. At least, I can find no mention in the manual, so maybe it was a different Aqua they meant.

Given there is no way to get RS232 data into the Z490 Aqua, it would certainly be possible to get the Uno to output a fan frequency signal, dependent on water temperature. I'm not sure though, how useful that would be - Is it possible to use a fan input signal to control fan output, using a monitoring program?

Thanks.