That's not the correct unit for my lexus

 

Whats the Year ,Make and model of your lexus and if you can please send my a picture of your original ballast thank you.

 

Unlikely. The failure on these denso ballasts is usually due to water infiltration because the ballasts are not very waterproof since they are usually mounted in locations far from water (ie- under or inside the headlights housings). You can see the corrosion on the circuit board he posted.

 

In the first post of this thread he posted the year and model of his car, and in laters posts we determined that the ballast in the car currently is the incorrect ballst from a later car. The one I linked from ebay (and the one you linked initially) were the correct ballasts for his car.

 

I ordered a used one from ebay like you suggested
do you think I can seal it with some silicone sealant or does it need to be open or it will overheat?

 

Don't crack open a good ballast. Silicone is not needed and will not help as the cable grommets are not waterproof and the electronics will overheat if the case is fully sealed.

waterproofing ballasts is a much more complicated procedure involving thermally conductive epoxy and working with high voltage electronics with capacitors. Best left alone or to those with experience.


Good luck!