hello

I recently purchased a discovery 1 5spd and am having an ongoing issue with the heater fan
the heater and AC work perfectly well, but when the interior lights come on when a door is opened it almost always blows the heater fan fuse.

the interior lights are also acting a bit funny, the lights over the read seats always comes on when a door is opened even if the front light is off.
the front light only comes on when the switch is in the middle position. the on and off positions both mean the front light stays off
the interior lights only come on when either one of the doors on the passenger side are open or the rear is open. neither of the doors on the drivers side cause the lights to come on.
I've pulled the sensor on the drivers door and found the wire to have been corroded off the sensor entirely.
could that wire be grounding inside the fender and causing the lights to short out the fan?
the interior lights cause the the fuse to blow even if the fan is not on
I initially thought the fan motor was on its way out so that has been recently replaced as well