Coolant pump runs automatically
It is a retrofitted used CNC lathe, the problem is the coolant pump runs as soon as the machine power turn on, and could not turned off by any way.
1- Check if there is any wrong wiring of the coolant pump.
2- The relay is broken or not?
3- Check the I/O board of the CNC controller.
In this case we found the relay contactor for the coolant pump was stuck, change it then back to normal.