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.