2005 prius intermittent no start

hi , I am working on a 2005 prius w/ a intermittent no start , b
12v battery is good , when it acts up you will have no dash lights , no imformation radio / heater , no power windows , you will have headlamps and 4 way flasers , when you push start button you will get a quik flash of check eng light only , park is not lite up either , ive cheked and cleaned every connection , sometimes it just works for days . only thing I found was driver rear taillight was leaking water and trunk compart was wet w/ water cleaned and dryed up compartment car was good all week , yesterday no start again , fooled w all day , waled away for 2 hours tried again car started right up. any help out there