I'll try to answer some of the questions ive seen here:
2009-2012 Rams:
These earlier trucks have a different computer system than the 2013+ models. They are notoriously picky, and the computers are quite sensitive to HID systems. Plugging some types of HID systems directly into the headlight plug can cause issues with the computer and even to the point where the dealer has to reset the ECU.
The computer is programmed to expect a particular system response ex:
" if there is a 55w halogen bulb plugged into this circuit> the expected current is X, the expected resistance is Y, the time dependency of these things is Z etc etc"
If you go and plug an HID system into this circuit, its starts freaking out because none of those variables XYZ match with the computer's expected parameters. Thus it thinks that there is something wrong with the headlight and will cut power, or try to reset the circuit. This is what causes flickering, periodic on-off events etc.
This applies to the fog lights as well.
2013+ Rams
These newer computer systems are programmed differently, thus they require a different setup in order to function properly. We (Enlight) have found that these need something plugged into the both headlight sockets or it will give you issues. A relay harness typically plugs into only one headlight connector, and the relay drives both headlights. We have a specific type of HID ballast with an integrated decoder module which works with the Ram's computer system to make sure its happy. But they are not compatible with the Pre-2013 Ram models.
If any is experience flickering, periodic on-off cycles or any other effects other than working the way they are supposed to, it will always do that. The cause is simply the improper system response from whatever HID setup you have.
As for fog lights, the 2013+ models are picky for fog lights. We have tried LED solutions which work well and do not flash or anything, but they cause radio interference for AM/FM when the fog lights are on. We have yet to try our latest HID system in the fog lights yet. The 09-12 models are less picky about what you put into the fog lights.
Hope this helps!