Oldsmobile 142456 Backup Lamp Bulb

In case of an inoperative tail, running or side marker light, ensure that there is battery voltage and ground on the concerned light's electrical connector. If battery voltage is present, check the bulb socket and the electrical connector ground terminal for proper ground. If both are present at the light connector but not in the socket then clean the socket and ground terminal connector. If voltage and ground are measured in the bulb socket then change the bulb; if not, then check the circuit using wiring diagram for open circuit. For this class of apparatus it's advisable to check the bulb for a bad filament and replace with another one if need be, look for signs such as corrosion on the exterior of the bulb and on its base and repair immediately any corroded wires and terminals and any other loose or damaged wires or terminals as well. Also, check or test the functionality of the light switch as well as replace it if necessary. If it is extremely weak, examine the bulb and socket for oxidation and clean or replace them and examine for low voltage at the bulb socket positive terminal or a bad ground. If voltage is low or the ground is marginal, crawl under the vehicle and look for any loose, damaged or corroded wires and terminals and repair, in addition examine the light switch operation and replace if faulty.