The light you will need is The Peterson Piranha Mini LED Clearance or Side Marker Light w/ Grommet - 1 Diode - Round - Amber Lens # M171A.
This light diameter of this light is 1-1/16 inches across the front of the rubber face, and is 1/2 inch deep it has 1 diode. It is compatible with 12V DC systems, and has a 2 wire design that includes the power lead and the ground wire. This light is more efficient and provides a brighter light with less power output.
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The 334850 part number you mentioned refers to the Replacement Control Switch # LC334850. This particular unit replaces the control switch assembly for certain Lippert Tread Lite RV Steps ( # LC353542, # LC353543, # LC353620, or # LC353621). view full answer...