diagnosing my kwikee steps

I've been having problems with my Kwikee Steps. They sometimes won't go out and stay out. I removed them from the motorhome and bench tested them using method described in the kwikee manual. All functions work fine (Door, Last Out, Ignition). After mounting the steps they still work perfect until the RV chassis battery is less than 12.4 volts. When the battery is 12.1-12.4, the steps go in and out, in and out (Won't stay out). But if the battery reads 12.5 or above, the steps work fine.
Battery starts the engine fine.

Do I need new Steps or Step motor or a new battery?

(Kwikee Steps Series 32 with integrated motor on the gearbox)