FYI... ALWAYS turn the ASC1 master power off when connecting / disconnecting distribution wires and coax.
With the ASC1 power on, the sensor wire S1 has power. I would expect to see a spark if this wire was shorted to ground.
The M1 /M2 wires only have power when the motor is being driven East or West. With a VOM test M1/M2 wires for momentary DC voltage when either East or West front panel button is pressed. The VOM should momentarily display 28-36Vdc. If no motor movement (or return reed switch open / close cycles), the ASC1 with cut M1 / M2 power and display an error message on the front LCD panel.
Did you try moving the dish from inside using the 12Vdc battery connected to the motor M1 / M2 wires coming in from the dish (disconnected from the ASC1)?