I had a semilar problem with my 180sx sr20det could not figure it out but the problem it wont start my lights everything worked but the fuel pump wasnt so i replace it with a new one because i was going to upgrade anws but the new one wasnt working either so we knew that it had to be in the wiring because like you we checked all the fuse everything looked ok i went to a guy that specialize in wiring and he cheked my harnass all the wiring and he solve the problem run me some new wiring and the car was like it was again it gave my headache because i bought sum new parts $$ the car was like for 3weeks park and ot was a litle problem in the wiring hope that could help
