Electric steps only retract with ignition turned on

In the manual it gives the two wires to test the magnetic door switch.
From manual page 8(?)To check the door switch, connect a
voltmeter between the red wire from
the 4-way connector (vehicle half)
and the brown in the same connector
(see Figure 8). The voltage
should be a minimum of 12 volts DC
Your voltage is still low. You should disconnect the connector and read the line coming from the switch.