No, they used internal limit switches if it's the kind I am thinking of,
i.e. MB stock Hirschmann 6000U from 1977 through sometime in the 80's.
Also maybe semi-automatic type where you let go of the switch when you
get the height you want.
The motors are all 12V either direction though.
JD
>I had a car once with a power antenna that you could raise to half height or
>full height. anyone know how to make this happen, what changes in the signal
>sent to the antenna , does it maybe go from 12v to 6v???
>
>