Utilizing Mach 3 on a cnc router. I setup a stand-alone 5-volt relay to run a 24-volt pneumatic solenoid for an air blast. I originally utilized Output 8 for controlling the relay. Initially for some strange reason, the relay was controlled off/on by the Reset button. I changed to a different Output and the issue went away and now relay works correctly.

I’m setting up another separate relay (same as first relay) and I’m having the same issue. I changed to a different Output and the Reset button triggers the relay off/ on again. I hope this is enough information for help.

Any thoughts on things I could check out?

How do you want to control the relay?

I will control the output signal via a macro. For the time being, I'm attempting to control through Flood or Mist command.

So have you set up the relay outputs in Config/Ports&Pins/Spindle Setup?  Then assign outputs to pins in the Output Signals tab?