My 2006 f250 power stroke electronic climate control. The fan comes on high when I turn the key to start position then stays on after motor starts. Can't turn fan off but can slow it by pushing a position button. I pulled electrical plugs behind unit three times but made no defference. I also pulled fuse. Second time for this last time pulling electrical plugs worked. Any other advice? Somebody must have an idea! Does the computor run this device or is it strictly it's own electronics? what I mean is can I buy a replacement climate control unit or does the problem go deeper in the vehicle?