I've been trying to get Mach3 to stop/start my router through a BOB connected through pin 17 to a SSR. I have the spindle relays activated and output 1 set to the proper port and pin.  I can get it to toggle on and off with the F5 key and with the spindle button.  When I try to run G Code command M3S20000 or M5 nothing happens. I have also tried to enter M3 and M5 in the diagnostic screen with no results.

I have read every post that I could find on the subject and am unable to find a solution.  Any help will be greatly appreciated.

I solved the problem! 

In case this happens to someone else the solution was easy.  When I installed Mach3, for some reason the macro files were not copied to the profile I set up for my CNC Router. I copied the files from the Mach3 Mill file and pasted them in the CNC Router file. Every thing works as it should now.

I am pleased you solved the problem and got the spindle working as it should.
Thanks for posting the heads-up on the solution.

Tweakie.