(h)  Ornamental lamps. A lamp not enumerated in this section and not located as described in Tables III, IV and V of this chapter, is prohibited unless it is available as original equipment. An illuminated sign is prohibited except on taxicabs, ambulances and trucks. Flashing or revolving lights are not ornamental lamps. Provisions relating to flashing or revolving lights are in Chapters 15 and 173 (relating to authorized vehicles and special operating privileges; and flashing or revolving lights on emergency and authorized vehicles).