12v RV light bulbs: The light bulb number can be found on the silver or brass base of the old light bulb. In many cases the number is stamped on the bulb base and is difficult to read. You may need to polish the metal base and have a magnifying glass to be able to read the bulb number from the old bulb. You may be able to match your bulb to the shape and base configuration in the chart below listing some of the more common 12v light bulbs used in RVs. Prices and ordering info for packages of 2 bulbs are listed below.