Head and dash board lights flicker on 2005 GMC Sierra 1500

I just bought a 2005 GMC Sierra and the head light (low beam) and dash board lights flicker. They don't seem to do it when i'm sitting still only when driving.

1 answer
Now all you have to do is find the loose wire/connection causing this, likely at the headlight switch. May have a pushed out spade connector that did not slide inside each other when plugged in.