Nissan Almera heater fan no go

I have a 2005 Nissan Almera n16 about 2months ago heater fan stopped working checked all fuses and relays, when refitting the fuse box (internal) banged the surround to refit and found fan working then 2 weeks after it stopped again I then went deeper and checked the motor for continuity and found ok checked voltage on pug and found 12v + refitted plug and fan worked turned engine off and restarted fan no go suspect electronics behind dash, since testing found fan works intermitantly I left engine running with air conditioning on after a few mins fan came on for just under a min and went off, air con pump working when turned on, can you please help