The media isn't part of the government. Technically the checks and balances was deisgned by the American founding fathers so that each of the three branches is checked and balanced by the other two in many ways like the following:

presidents vetoing a bill passed by Congress

Senate confirming executive appointments

the judiciary declaring the constitutionality of laws (which I don't think is actually specifically spelled out in the Constitution, really the Constitution just allows for the judiciary to interpret the laws, and Chief Justice John Marshall interpreted that to mean the judiciary could nullify laws it felt went against the Constitution.)

President appoints judges/justices, and the Senate must approve.

etc.

Elections have nothing to do with checks and balances. That's just part of democracy, and so is a free and independent media.