Just crank up the ambient value ; in some cases I set it to 100 or more, depending on the distance.
If your light prop has a material for the lightbulb inside, use that material to set the ambient on.

If the lightbulp has no proper own material, you can make one with the grouping tool.
Or?
Load the simple ball prop, and scale and place it to imitate the light bulp, and put ambient on the ball to simulate the lightbulb.

 Euh, IDL is a requirement for ambient to work.... and set Raytrace bounces to at least 2-3

 

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