I turn the key, one loud click then no power. Dash goes dark. Dome light goes off. Light under hood goes off. I disconnect the battery and try again. Same result. ICM replaced back in spring. 1992 F 150, 5.0 V8, 66k original miles.

 

Start by removing both battery cables from their battery posts and cleaning the insides of the cables where they hook to the posts. Also clean the outsides of the battery posts. Clean these surfaces shiny clean and then reconnect and make sure the cables tighten up properly. Always disconnect the negative cable first and reconnect it last. This will solve your problem the vast majority of the time so start there.

If no joy there follow the positive battery cable to the fender mounted solenoid(relay) and make sure the bolt is clean and tight where this cable hooks on with the other smaller cables. No joy there follow the negative battery cable to where it hooks and remove the connection and make sure it is clean and tight. No joy yet maybe one of the main battery cables is bad and shorting internally.