Put the (+) lead on pin 4 and the (-) lead on a good chassis ground.

With the wipers parked, pin 4 to the chassis should read open circuit (high resistance).

When the wiper operating, the ohms reading should be very low - like maybe 1 or 2 ohms (ideally zero but the reading depends on the leads etc.).

__________________
Wayne
2005 BMW X5 3.0d (b 02/05)
2001 BMW F650GS Dakar (b 06/01)