Stop it running.
It is probably running continuously because the limit switch is enabled for the A axis. When you REF the machine the axis starts rotating. You really don't need a limit switch, so disable in the config (pins etc..)
Now just JOG it around to zero using page-up/down and zero the DRO.
A45 now moves to 45 degrees. Depending on the config page settings A-5 or A355 may go the long way from here, or the short way. I like the short way.
I prefer to fit a 6 pin plug (with at least 5 amp contacts) on the 4th axis.
6 Pole JAYCAR IP67 multipole connector and socket is perfect. There is also a screw cap cover available.
It is VERY IMPORTANT that the power is off when plugging or unplugging 4th axis. A voltage spike can damage the driver and void your warranty.
Super X3. 3600rpm. Sheridan 6"x24" Lathe + more. Three ways to fix things: The right way, the other way, and maybe your way, which is possibly a faster wrong way.