MacBook Air fan on for no reason

hi,

I have an early 2015 MBA which was closed with around 45% battery last night. When I opened it up this evening, it would not respond and came up with the icon to suggest the battery was flat.

I plugged it in and noticed after a couple of minutes, the fan was on (loudly) and was quite hot around the fan area.

Steps I have tried to resolve it are:

• I have restarted it with no apps or programs running but still the same thing.
• I have looked at the activity monitor and initially the kernel_task was using both a lot of CPU and memory. It is now just using a lot of memory and there is nothing using anything significant regards to CPU.
• I have done an SMC reset
• I have done a AHT which reported no issues

So my guess is that it is a some software somewhere, rather than the dreaded logic board which died on my previous MBP!

Any thoughts or input most welcome.

Thanks for taking the time to read this.