For the past three days the interior blower fan will not turn off after shutting off the ignition, ultimately it runs all night and the battery dies and must be jump started. It's not the fan associated with the engine or radiator but a cabin fan of some type. I know that there is a built-in fan that can run for 5-6 minutes by design after you turn the ignition off and that this is normal, but that is not what is happening, it will run for hours and hours. Nothing basic has worked, such as starting the ignition and turning it on/off several times. It seems that the fan is running at a very low mode, but regardless if just never turns off.

Trying to prevent having to take it to the dealer and spend hundreds if there is a self-serve solution to this problem. Any advice on what to try from those who have come before me ?