2000 XJ ~160K miles

So I went to change the master window switch. Typical issue - driver's window worked but no others did. Replaced it but all windows only worked with driver's control. Tried the bypass of the lockout -ok. Now after three days I go to start my jeep and nothing turns on. I turn the key and absolutely nothing happens, no cabin lights, no dash lights, no starter. So I get a jump and no go. I take the battery out, get it tested and its good. I clean all terminals and cables. Now cabin lights come on sometimes. They may or may not come on each time the door opens. Sometimes bright, sometimes nothing, sometimes dull. Then I try another jump. It works and jeep fires up like normal- all lights cabin/dash normal. Unhook cables turn off and try to crank. Fires right up everything normal. Wait a few minutes and turn it off and try one last time. Nothing - no lights no starter no nothing. What the hell? I would love some help if anyone has any ideas. I figure it must be a short but don't know where to look or what to test. Thanks

 

I know you cleaned the terminals at least once, but still. Lead can get an oxidized coating and can look pretty good and still have a hard crust. You want bright shiny lead on all four contact surfaces. Really sounds like an issue there. I'd use a pocket knife carefully on the inside of the clamp. Also having it work when you jump it....course that would by-bass a bad connection there. That's all I've got, good luck!