Hmmm... It all started when my battery went flat after leaving music on for a few hours. We jump started the car (something coulda possibly happened there).
And yeah, the car would be idling at 800-900, then if I turn either of those lights on, my revs would drop to 500 for a few seconds, voltage drops to 12 or something, headunit restarts, MFD restarts, airbag light would come on (like normally when you start the car), then a few seconds later, everything will return to normal.
Revs would go back to 800-900, voltage will go back to 14 or so.
Also, another symptom of this is, when I'm idling at the lights with my indicators on, the whole dash light will dim with the indicators, which means even the indicators are causing problems, but I guess the load isn't as much as highbeam, so headunit and MFD stays on :S