Late 2014 Desktop here Larry.
Hmm....Does sound like it's working if you can manually trigger it
"the bar that is suppose to trigger it " Mine doesn't have a bar...it triggers off the lower bearing block itself, so can't help you there.
But, have you inspected the trigger to see if it's been worn down/broken?
When pushed to the left is input 3 light coming on?
Contact and trigger cleaned? (Padauk dust has caused mine not to trigger a couple times).
NOT that expensive to order from Shopbot Sales if I remember right from ordering a replacement years ago(my fault it got pranged).
Would the thickness of a Very High Bond double sided tape help?
Sorry not more help.
scott
Does it even look like the switch in my pic?