Weird spindle behaviour

[loesch]

I have a Stepcraft 600, switch box, and a StoneyCNC Industrial HF spindle. All was working fine using UCCNC 1.2112. Recently, I noticed that if I turn on power to the spindle, then run UCCNC, the spindle comes on and goes to max speed. I've checked the spindle settings in UCCNC per the manual for the spindle and all seems correct - PWN on pin 17 and M3 relay on pin 1. I can run the spindle manually, so that part is working. I eliminated the switch box and plugged the spindle directly to the Stepcraft. In UCCNC,I can run the M03 command or use the CCW button on the screen, output pin 1 toggles correctly as relay M3 is defined as pin 1, but the spindle does nothing. The only thing that looks out of the ordinary is that output pin 16 is flashing. According to the Stepcraft manual, pin 16 is listed as relay 3, but I don't know what relay 3 is or if it's even used.