By Luc Olinga Major banks report third quarter results, which should give an indication of the health of the US economy and financial system. The moment of truth is approaching. Investors, experts and regulators, who wonder about the health of the American economy and the banking system, will finally have a first and clear diagnosis. JPMorgan Chase , Wells Fargo (WFC) – Get Wells Fargo & Company Report, Citigroup (C) – Get Citigroup Inc. Report and Morgan Stanley (MS) – Get Morgan Stanley Report, four of the major U.S. banks, release their third quarter results on Oct. 14, data that should giv…