One cooling fan not working

[Steve-w5bag]

Hoping someone can help me fix this cooling fan issue on my Griffith 500 (1996)

The LH cooling fan is working but not the RH
I've checked the relay and replaced the fuse, the old fuse had not blown, but a put a new one in anyway (40a Fuse)

I've swapped the fan wires over, on doing that the problem swapped to the opposite fan, The LH stopped working and the RH started working so its not an issue with the actual fan its self.

Any suggestions / help would be appreciated

Thanks