C4 Fog Light question

[Craig P.]

I have been unable to find a definitive description of the fog light lens for my 1991 Coupe. This question came up at a Flight Judging event where it was suggested it may possibly be condensation, but it was undetermined. Contained in the same sealed unit as the turn indicator, the turn indicator lens appears clear, but the fog lens appears frosted. Both left and right exhibit the identical condition. Both sides appear identical, and very uniform - from the outside it does not appear to me to be a moisture issue. The car is garaged, and is only very rarely (once every two or three years) driven in wet conditions. None of the literature that I can find states if the lenses are clear or frosted - there is simply no description at all that I can find.

Does anyone know for certain if the C4 fog light lenses are clear or frosted? Is there any known literature that states this?? I wish to pursue a Regional or National Flight Judging process, and would like to know more about this topic.

[Mark E.]

Re: C4 Fog Light question

Craig,

1991 is one of my favorite years! The L98 is an attractive Corvette engine and well showcased with the clam shell hood.

Can you post a photo of the lens? Both the fog and parking light lenses are uncolored with light diffusers molded into them. Here's a photo of one on eBay: https://www.ebay.com/itm/144204530741

The diffusers make the lens a bit opaque (meaning the lens does not transmit light directly like a flat piece of glass) but I wouldn't call the appearance "frosted". It's not uncommon for condensation to build up in these housings and cause what you describe. Moisture can seep in while washing or a heavy rain if the bulb socket isn't well sealed to the housing. It's interesting that each side is identical, so a photo would be helpful.

If it is moisture, remove the socket from the housing and blow with compressed air (or use a hair dryer on low heat if you don't have a compressor). The idea is to displace moisture that's trapped inside.

I doubt you need to remove or replace the housings. But if you do, this requires removing the bumper cover to get to them.

[David H.]

Re: C4 Fog Light question

... This question came up at a Flight Judging event where it was suggested it may possibly be condensation, ... ... I wish to pursue a Regional or National Flight Judging process, and would like to know more about this topic.

Craig

I don't remember off the top of my head. As Mark indicated above, a photo will be most useful. From your description, lenses appear to be original.

That said, condensation would be considered a "Condition" issue. Front Parking, Fog, and Cornering Lights are judged together. There are 12 Originality, and 12 Condition points associated with those three items. Typically, judges would spread those 12 Condition points over those three lamps, assigning 4 points to Fog Lamps. (Two (2) points per side)

As described, your condensation would be considered an "easy" fix - generating at most a 25% deduction. As this Condition exists on both sides, deduction would be at most 25% of 4 points yielding a 1 point deduction. All Flight cars start with 4500 points total.

(If only one side was effected, then half point - some judges might round up to a 1 point deduction, while others might write a note with no points taken.)

Post a picture.

Dave

[David H.]

Re: C4 Fog Light question

Craig

Do your lenses look like this eBay for sale item?

Dave

s-l1600-1.jpg

[Craig P.]

Re: C4 Fog Light question

Here is a photo of both left and right lights. Hard to see in the pics, but perhaps the Driver side is easier to see what I am talking about. You can see a bit of glaze on the fog light (inboard) as compared to the turn indicator (outboard). The pics don't show it well, but left and right appear identical mirror images of each other... Would it make sense that the fog light is a bit frosted or glazed to help diffuse the light for foggy conditions?? I do not believe this is anything I would swap out, but I also covet every point I can retain in flight judging...

David - the eBay picture you posted appears to be a Driver side module. This pic also appears to have a frosted lens as compared to the turn indicator, but again it is hard to tell in a photo...

C4 Fog Light.jpg

[Mark E.]

Re: C4 Fog Light question

I enlarged your photo. It's pixelated and a bit out of focus so it's hard to see detail. Maybe the photo is misleading because the driver and passenger side look different (driver side looks more cloudy), while you say they're the same.

Two thoughts-

- As David said, this issue isn't of much consequence from a judging perspective.

- Rectify this if it matters to you. First step is blowing out the housing as described above to see if moisture is the issue. I suspect it is. I suppose it's also possible the plastic in the lens has clouded because it's defective or weathered.