Hello Justin,
We appreciate your response. There are many factors that affect why the fan is constantly running. It can be due to the number of programs running which take up the Surface resources, or the device working to maintain each processes. It can also be a symptom
of a hardware failure. Please be advised that the fan turns on at 48 degree Celsius (or 114 degrees Fahrenheit). The temperature icon will appear and the device will shutdown at 50 degree Celsius (or 122 degrees Fahrenheit).
To clarify, can you tell us if you were able to perform a clean boot as mentioned above? Was the behavior the same even when device is on a clean boot state? If yes, we suggest that you run a power/energy report. Here's how:
Step 1: On the Search bar/Cortana, type 'cmd' to search for the Command Prompt then press and hold or right-click and select 'Run as administrator'.
Step 2: On the Command Prompt, type 'powercfg /energy' and wait for the result.
*In case there's no report generated, exit the Command Prompt and restart your Surface then repeat Steps 1 & 2.
Step 3: Once there's a report being generated, follow and open the file location of the said report. (It will appear as 'energy-report.html').
Step 4: Once you open the report, kindly send the screenshot with your reply and/or upload the file via OneDrive and share the link so we can check it on our end.
Keep us posted on the outcome.