..

 

Do you get flicker when the engine isn't running?

 

..

 

Then either the alternator is introducing noise or the extra voltage is causing the issue. Do you have a battery charger? That way you could bring up the voltage to about what the alternator supplies.

 

..

 

Old HID bulbs tend to flicker or go out after operating for several minutes (hot bulbs). After cooling they may operate normal.

 

..

 

By not having the car running, you'd be running the headlights on battery only. Battery voltage is relatively clean/smooth direct current.

When the engine runs, the alternator is also running and topping off the battery. Alternator output is relatively dirty, even on a properly working one, with multiple ripples/differences in voltage. However on a properly working alternator, those ripples would be small enough you wouldn't notice them. In an extreme example, the ripples could be big. Think of when you shutoff a car. The voltage goes from 14.X to 12.x, and you could usually see lights dim a little. Now imagine that multiple times a second.

If the issue is happening only when the car is running, then it could be a bad or failing voltage regulator in the alternator. By hooking up a trickle charger, you are adding voltage to the system while the car is off to mimic the alternator charging the battery voltage. That would check to see if maybe one of the headlight components is failing and only doing so with the higher 14V running voltage.

If the issue happens with car off, then it could be a lose or dirty ground/power connection, or a failing component in the headlight system. Make sure all battery terminals, and any ground points near the headlight are nice and tight.

 

..

 

check the headlight to see if it is sealed...moisture gets in and causes the HID to flicker...common problem