Bayern are off the pace in the top flight, but Heynckes has called for a united front, asking his more experienced stars to replicate the previous influence of Philipp Lahm and Bastian Schweinsteiger.
The 72-year-old told reporters: "These players sorted a lot of important things in the changing room. We need that again, to give the other players more confidence. Success is the most important thing. From a sporting point of view, many things must be changed and improved.
"It's no secret that Thomas Muller isn't playing to his full potential, or that Jerome Boateng has struggled after a series of bad injuries. I know what I have to do. I need to sit down and speak to the players, and re-instil that feeling of togetherness. I have a clear plan.
"Despite this difficult phase, I am confident that the team will quickly show a different side."
Heynckes's first match in charge is an encounter with Freiburg at the Allianz Arena.