The ornamental design for a truckheadlight, as shown and described.
FIG. 1 is an exploded perspective view of a truck headlight, showing my new design;
FIG. 2 is a perspective view thereof, with the lens removed;
FIG. 3 is a perspective view thereof;
FIG. 4 is a front elevational view thereof, with the lens removed;
FIG. 5 is a front elevational view thereof;
FIG. 6 is a front elevational view of the lens thereof;
FIG. 7 is a rear elevational view thereof;
FIG. 8 is a left elevational view thereof;
FIG. 9 is a right elevational view thereof;
FIG. 10 is a top plan view thereof; and,
FIG. 11 is a bottom plan view thereof.
The even-broken line in the figure drawing views represents unclaimed environment structure of the truck headlight only and forms no part of the claimed design.