Within forty-eight business hours of notification by City, contractor shall diagnose source of malfunction within said light or lighting system. If malfunction involves lamp, ballast, photo cell, leads, contacts, sockets, or other minor parts, contractor shall immediately replace said malfunctioning part under the time and materials payment schedule. If the malfunction requires more than minor repairs, contractor shall provide a written estimate of the time and material cost to the City for authorization prior to performing repairs. City reserves the right to obtain bids from other contractors for any repairs estimated to cost over ten thousand dollars ($10,000). The contractor shall clean said components each and every time a service call is made to the fixture under the terms of this contract. Said service call cleaning shall consist of wiping the lens, refractor, opal glass with a clean, soft cloth so as to remove all dirt, dust, and foreign matter. Contractor shall be responsible for obtaining any required permits and for providing all necessary traffic control.