Relay Click
 

When looking under my dash I noticed a relay that was unplugged so I plugged it back in.
Ever since the relay clicks on at 2000rpm and off when it comes back down to 2000rpm

Looked at the wiring diagram and it looks to be the Blower relay.
But the interior fan worked when it was disconnected???

Any ideas what it is and why it would be connected to the engine revs??

Shall I disconnect it again or just ignore it?

Thanks
Scott