The ornamental design for a vehicleundercarriagespraywand, as shown and described.
FIG. 1 is a perspective view of a vehicle undercarriage spray wand showing my new design;
FIG. 2 is a front view thereof;
FIG. 3 is a rear view thereof;
FIG. 4 is a side view thereof;
FIG. 5 is a top view thereof; and,
FIG. 6 is a bottom view thereof.
The broken line showing of a vehicle in FIG. 1 is included for the purpose of showing environment of the vehicle undercarriage spray wand and forms no part of the claimed design.