I own a 2004 Chevy Express cargo van, which has a front horizontal mounting lens that covers 4 exterior light bulbs. Several of the bulbs are burned out, and I don't know how to get at the bulbs to replace them. The older vans had screws attached to the mounting lens for easy removal, but my van has no such apparatus. Most Chevy manuals give instructions for removing bulbs on the older vehicle. I cannot get at these bulbs from the top or underneath the vehicle. It looks like something has to be removed to get at the bulbs. How are the bulbs replaced?