In a few cases on Terabot, we have seen the part cooling fans not turning off despite them being set to be off in Simplify3D. This has caused issues of thermal runaway and poor print quality. The way to remedy this is as follows:
In the tool change script change the M106 S255 to M106 S[fan_speed_pwm] as shown below.
After making this change, press the "Update Profile" button next to the "Select Profile" drop down list in order to save the changes to prevent this from happening in future prints.