1951 Fog Light Bulb Cover

[Steve Strickland]

Are the bulb covers on the fog light bulb really needed for their operation?

I am in the process of rebuilding my fog light housings and only one bulb had the cover on it. I have found them on ebay, but won't buy them if they don't really make a difference. I've never seen them work on my car, so I can't compare how one side was to the other. Thank you in advance!

[The Tassie Devil(le)]

The only reason there would be a cover on a Fog light globe would be to direct all the light back onto the reflector, which then would display the beam in the correct pattern for illuminating under the layer of fog.

Allowing light to shine straight forward from the globe would throw light upwards, thereby diminishing the ability to observe the road through the fog.

Bruce.

[Steve Strickland]

Thank you Bruce!

[Cadman-iac]

Are the bulb covers on the fog light bulb really needed for their operation?

I am in the process of rebuilding my fog light housings and only one bulb had the cover on it. I have found them on ebay, but won't buy them if they don't really make a difference. I've never seen them work on my car, so I can't compare how one side was to the other. Thank you in advance!

You're speaking of the triangular snap on cover I'm guessing.  I was wondering the same thing myself. Out of three cars, I had a total of one cover.
I'm thinking that it's not absolutely necessary,  but it would help deflect the light back to the rear of the lamp to help defuse the beam. You don't want a bright straight forward beam in fog, or it will reflect back at you making visibility difficult.  Kinda like using the high beams in fog. It doesn't work well.
Rick

[Steve Strickland]

Thank you Rick! I have ordered a set off of eBay.