Please see pics. Top is the headunit, below is the EQ. I have the harness for the headunit, but I don't have whatever connects where the 4 pins are in the EQ (lower right). Do I need a harness for the EQ?

I'm not familiar with the RCA connections. I guess the two RCA outputs from the headunit go to the EQ RCA connections. But how do I power up the EQ? Seems to me that I need the harness. Please advise and sorry for the naive questions. Last time I installed a unit was "wire-to-wire".

Thanks