Issue with battery or IO/DC power board?

I have a mid 2011 11” Macbook Air that appears to have an issue with the battery or the dc power board. I have a few questions and I’m hoping someone with more knowledge will be able to answer them.

The 2011 A1370 powers on without a battery but the fans immediately kick into high gear and continuously run as long as the machine is powered on even though the board remains cool/appears nothing is overheating. Is this normal behavior for this model?

Is it possible to reset the SMC without a battery installed?

Are there any thermal sensors located on the trackpad or somewhere else in the top case on this model?

If I also unplug the IPD/keyboard flex cable the machine turns on but the fan doesn’t even turn on.

I’ve had this machine for a while and when I had a replacement battery for it i recall it exhibiting various strange symptoms and I never got it to work properly so I returned it and left this thing sitting in a corner for the past few months. I’m now looking at it again and trying to figure out what exactly i overlooked the first time. I have checked out the logic board, took some readings, looked for shorts and everything appears to be good. Could the IPD cable or the IO board be causing an issue that would affect the battery?