The ornamental design for a lighthead for a vehicle, as shown and described.
FIG. 1 is a perspective view of a light head for a vehicle showing my new design, with the center portion broken away to indicate indeterminate length;
FIG. 2 is a front view thereof;
FIG. 3 is a rear view thereof;
FIG. 4 is a left thereof, the right view being mirror symmetrical; and,
FIG. 5 is a top view thereof, the bottom view being mirror symmetrical.
The broken lines depict portions of the light head for vehicle that form no part of the claimed design.
The separation and bracket indicate, for ease of illustration, that the precise length of the light head for a vehicle is not claimed.