We had a spontaneous failure to extend on our 2-step Kwikee steps during a recent outing also and I am part way through the troubleshooting. There had been no issues otherwise and it operated smoothly up until 1 hour before failure, with regular applications of KwikLube
The step lights light when the door is open, so the door switch is good.
I am waiting for a response from Powergear for a 4-wire connector pigtail that is required for part of the troubleshooting procedure.
So far I've verified one side of the 4-wire connector, that verifies that the 12 volt power to the step is good with a good ground, that the ignition switch lock-out is working correctly, and the door switch bypass is working correctly. The 4-wire pigtail is required to manually drive the other side of the 4-wire connector. Another step is to disconnect a 2-wire connector from the control module and connect directly to a battery to verify that the motor is good, ie the steps will extend, reverse the connection and they will retract.
I suspect the control module failed but have a couple more steps to complete to verify.
And BTW, a 2-step stepladder is a good work-around in the meantime.