Like I said earlier, you generally have:
1) Battery circuits - On all the time. Examples: dome light, clock, headlights, hazzard lights
2) Ignition circuits - On in the IGN position. Example fuel pump, ignition system, turn signals, guages
3) ACC (Accessory) circuits - Wipers, HVAC, radio, heated seats
4) Start: enables starter, drops all ACC circuits while starter engaged.
4-way flashers and turn-signals can be a bit wierd, Flashers are on all of the time. Turn-signals only in IGN.
Dash illumination can be wierd too. Depends on the vehicle.
Some guages like a voltmeter might not drop.
Some indicators are not affected by dash dim. examples: Traction