EndStop Issue: LED dim/flickers, False homing, Help?

[Ottobawt]

D300VS Delta.
I've attempted to fix by replacing switch and sinch up the wires involved.

The LED on the board is dim/ not fully on/off, making it impossible to home.
I've attempted disconnecting/reconnecting the switch, which sometimes can get it to perform as intended, but can also go back to a dim state at random.

Help? Suggestions?

[dc42]

Is the endstop a microswitch, or some other type? If it's a microswitch then the most likely cause of the problem is a bad crimp connection in the cable.