Mine have never extended without permission but have failed to retract when I start the engine door closed .. This is a problem, I think I know why they do that.
BUT.... I did the following
From auto parts store I got a automotive door jam switch, There are assorted designs of these but functionally most all of them work as follows
No pressure on plunger, Switch is closed (It is a "normally closed" switch)
And a L-Bracked from the buliding supply store THe one I have is fairly thin metal and about 1" wide by 1" on a side_
Driled hole in bracket and mounted switch
Mounted bracket to steps frame (The part bolted to the motor home) in such a way that when RETRACTED the steps press the button and open the switch
The electronics
12 volt from IGNITION FUSED----12 volt LED assembly-----Switch
If the steps extend.. LIGHT ON