I wouldn't bother, unless it's trivially easy or you have another reason to add a fan.WillAdams wrote:Fan --- to cool extruder
You've got some (quite serious?) problem with the machine that is not due to it not having a fan.. Adding a fan might lessen the symptom but the problem will still be there.
I like cvoinescu's idea of the PID being really screwy. If nothing else, it's probably easier to test & fix firmware issues than electrical ones.