The Chinese found a way to get a bulb to work with both the D2S and D2R in one base...the D2C
D2C based bulbs usually have
horrible quality bases and bulbs...so plugging them in, you tend to have problems with the connection...showing up in exactly the way the OP stated..lights going on and off..not going on at all. It's the connection of the D2C bulbs causing the issue.
Please stay with the D2S....you wont have these problems, and you didn't save any money.
from HIDPlanet.com
"D2C are cheaper Asian made bulbs keyed at the base to fit either D2S or D2R. They would be a disaster to replace D2R, blinding everyone in sight. They are by definition cheap junk. You should never buy D2C only D2S or D2R as the originals were."
"Yeah..the D2c's a designation that the aftermarket cheap bulb manufacturers have come up with. They are too cheap to make seperate D2S and D2R bulbs so they made one that will fit both.
Dont expect much performance or lifespan from them if you get them"
also to trouble shoot....reinstall your stock Phillips 4300K bulbs and see if your getting the same problems. If you're not...it's obviously the bulbs and their connection.