yellow lens

The lens is made of polycarbonate plastic. The ultraviolet rays from the sun will cloud it up and turn it yellow. You may be able to use a plastic polish and remove some of the surface damage. Your lens sounds bad and it is likely the damage goes deep into the material and the lens must be changed.

Another problem is moisture can get inside the lamp and it can damage the silver coating. I had this on my 89 Escort on the driver side, and it made the light from the lamp look yellower and dimmer. John

My 97 Taurus lens had become quite yellow, and one day I tried rubbing them with denatured alcohol on a soft rag. I cleaned all of the grit off first. Amazingly, much of the yellow came off. Then I used another soft rag with naphtha (cleaning solvent), and more yellow came off. I alternated back and forth, and before long the lens was clear. But it still has scratches & pits from road debris. This helped considerably for night vision.

I think the yellow comes from water spraying up from the road in wet weather, and the stuff used to melt ice in the winter. Sunlight acts on that and turns it yellow.

There was a post here a while back where someone used Turtle Wax Polishing Compound on the lenses, but I am reluctant to try that.

You might try an aviation supply house - small private plane owners have a way to polish the windshields of the aircraft with a special sandpaper.

GT

i got a 96 contour that HAD the yellow headlights.. its the lenses that are deterioating due to the plastic in the suns rays thats breaking down the plastic... i get a can of Turtle Wax polishing compound from auto parts store for $1.89 a can.. wet an old face cloth and work on the lenses for about 15 minutes each.... then wipe off with wet rag.... i checked mine with a pair of head mounted magnifing lenses.. could see the tarnish on the lenses and worked it until it came off.... i left the hood open so the compound would not mess up the paint on the hood area and used some duct tape on the sides and bottom of the lenses so the compound would not take any paint off the painted parts of the car..... used an electric drill with a polishing bonnet on it to polish up the lenses.... it will last about 6 months like this.. and you have to do it again as the rest of the plastic is starting to tarnish... just like polishing brass.. the weather get to the brass, the sun get to the plastic.....