What ballast do I need for a 2004 CTS (HID bulbs)? Best price? Thanks.

the older cadillacs generally do not come with hid lights, you need to get an adapter kit to be able to install them or purchase entirely new headlamps, its not just a bulb thing

It is better to change the light out with LED's and get rid of the neos all together or you will be doing the repair again within a year. We replace the interior with LED's and make sure the interior is waterproof just in case water does get in there. Just call 863-253-1810 or email me at rushnash3@yahoo.com. Ask for Rush! We can do this repair for only $150.00 plus shipping. Just detach the light and send it to us. make sure you wrap the light in bubble wrap, and that will save the light from damage in shipping, also mark as fragile. Send it to us and we turn around the light in most of the time the same day or at latest the next day. We look forward to assisting you!

I had the same issue, headlight casing was leaking, ballast was drowned. Take the ballast out, gasket and all, and put it under a low set heater or lamp, or use the rice trick (No I'm not kidding). The HID ballasts for the 03, 04 rely on a ridiculously big current, so the input is usually enough to shock it all into order again, like using a bigger motor to shake the rust off of a mechanical system.