I've checked all three stop switches. They all function as expected and display "Hit" when manually actuated. I have "wiggled" the wires (don't know the technical term for checking wires) and they all seem to be in good condition.. The behavior of the extruder when I select Auto Home from the panel follows. The initial state of things before executing Auto Home are the extruder is centered over the bed and sits about 60-80mm over the bed. The bed is centered under the extruder in the Y direction. The bed-leveling probe is extracted. On execution:
1) The extruder moves towards the X-Stop,
2) The probe is extended when the rack hits the left carriage,
3) The bed moves towards the Y-Stop.. at the same time the extruder begins to move away
from the X-Stop towards the right carriage,
4) The bed hits the Y-Stop and begins to move away from the Y-Stop. The bed stops
after moving a little more than 200mm,
5) The extruder continues to move towards the right carriage until the rack hits the
carriage and retracts the probe. (It does NOT crash into the right carriage). Once
the probe retracts, the extruder then begins to move towards the bed.
6) When it is apparent the extruder is going to crash into the bed, I turn the power off.
On one occasion, when the extruder hit the right carriage and retracted the probe
I manually operated the probe switch. The extruder stopped, rose a bit, and then
started descending and a slower rate (just as if it would do if it were doing a bed
leveling - which it wasn't... it was still trying to Auto Home) - anyway after manually
operating the probe switch again, the extruder then tried to continue its move to the
right. Since it was already sitting as far as it could go to the right, the stepper just
growled as attempted to spin through the cog-belt.