What was found
AIR TURNBACK - LLCCAFR SWITCH IN POSITION "BOTH" TEMP SELECTED FOR 7° LOWER FORWARD , AFT MAIN DECK, FWD AND AFT. THE AIR IN THE COCKPIT WAS UNCONTROLLABLE - HIGH PRESS AIR BLOWING AROUND NAV DISPLAY - SELECTED THE LLCCAFR SWITCH OFF TO CONTROL THE TEMP IN THE COCKPIT CAUSED A BURST OF MIST COMING FROM AND AROUND ALL NAV DISPLAYS & MCP PANEL. THE COCKPIT FILLED WITH A STRONG ODOR OF OVERHEAT. LOST EICAS DISPLAYS AND PFDS.