It sounds strange, but it's true: A Dallas 1-Wire^TM link requires up to three wires!

(1). The actual 1-Wire^TM DQ data line;

(2). Vdd supply line;

(3). Ground reference line.

If you already have a suitable Ground line, you can do away with (3) - so only two extra wires are needed;

Most 1-Wire devices can be "parasite" powered, where the DQ data line also provides the power feed - if this works for your application, you can do away with (2);

If both of the above apply, you can do away with both (2) and (3) - and you do end up with just one extra wire!