6X4 diesel cooling fan - no voltage

Hi folks, I'm pulling my hair out over the cooling fan in my 2004 6X4 diesel Gator. There's no voltage to the red wire that connects to the fan. I replaced the relay with a used one but still no power to the red wire where it connects to the fan. There is voltage on two of the four wires at the relay.

Can someone offer any advice? Can I test the relay?

THANK YOU!