[Al Skierkiewicz]

OK,
As I read your post you are referring to pins 2,3,4. Does this imply you have four pins? Is this not the pot supplied in the kit? If this is the kit pot then connecting 5 volts to one outside pin and ground to the other outside pin will yield a variable voltage on the middle pin. Ground does not mean the frame of the robot but the common of the battery. Without a return path to the battery negative terminal, the wiper of the pot will be at +5 volts (or very near 5 volts) for any postion of the shaft. This is "open circuit" voltage. When no current flows through a resistance, ther can be no voltage drop. Ohm's Law V=I*R
Al