Just recieved my 6000k and 8000k replacement d4s/c HID bulbs. installed them. one of the bulbs works fine. the other lights up and shuts off. i have to turn the lights on and off at least 5 times in order for the faulty one to stay lit. so heres my question. bulb problem or ballast problem?

 

bulb problem burning ballast?

 

If you didn't have any problems with your HID bulbs before replacing them, then most likely the problem will be the new bulb you installed. However, what it sounds to me that could be your problem is that the bulb wasn't properly connected. I would take out the bulb, clean it all with isopropyl alcohol and reinstall it again, making sure the connector hooks up to the bulb properly. If it stills gives you problems, then just contact the company that you bought the bulb from, and have them replace it.