Originally Posted by
onehundred80
The fan will come on with the ignition OFF, it is used with the operation of the REST heating function. That means that the switch will get power from some constant power source, the REST button is on the dash, maybe that is a good place to start looking. The engine coolant pump will also run, can you hear it under the hood?
The REST button is in the heating/AC control panel on the dash so as that part has caused many problems in the past it is a good place to start.
Good catch, didn't think of that since almost no one ever uses it ( at least around here ).
BTW, I have a spare one of those pumps, it is not an "engine coolant pump", it is only for circulation through the heater cores while you are RESTing.