Spindle on off problem with M3&M5

using spindle control to start plasma cutter, using the buttons in linuxcnc every thing functions as suppose to. M3 works as supposed to,m5 wont switch the relay but will show stop button pressed in manual. by inverting the pin in linux cnc M5 works but not M3. does same thing using F9 or f10

Neil,
Can you please run a gcode file that has M3
Do something x y
M5
M2
If you run that and you can see the buttons on Linuxcnc screen change state, but the relay does not, that must have something to do with hardware, not software.
You can also check that by using hal configuration in Linuxcnc and watch the pin that controls the relay.
What hardware are you using, and what config?
Regards,
Tom

I can visually see the relay switch when I click on the manual buttons,when I go to the other screen and type m3 can see the relay switch, type m5 relay no change go back to manual screen the off button has been pushed have to hit start button then stop to get relay to change.