Why are my headlights flickering on 2013 Venza

Question

When I turn headlights on they tend to flicker as if you're signalling to on-coming traffic that a police car is ahead.

Answer 1

Turn on the headlights with the engine off, if they stop flickering when you turn off the engine, then your alternator is most likely bad. If they still flicker with engine off, the alternator is good, and the issues lies somewhere else e.g. bad wiring, bad ground, bad bulbs, etc.