I have searched the Lippert site, and can’t find any reference to a “Stairs extended” alarm.
My guess is that the coach builder added this.
This means they likely added a switch which is activated by the movable section of the steps.
If the switch is not waterproof, then the wet contacts could give you the false alarm.
Take a look under the steps, there should be a single control module. Then look around for additional wires that look like they have been added…or look for the extra switch.
OR..they may have tapped into the under-stair light and used that to sense when the stairs were extended. This would have to be combined with a ignition-hot wire which would then trigger the alarm.
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