Electronics help

Hi

I’m trying to add a remote control to a water pump circuit but struggling to get my head around things. 
 

Below is the manufacturers wiring diagram and I want to add a remote control unit,  this has 4 wires,  2 positive and negative input and 2 for output.  It needs to work after the speed controller. I want to be able to turn the speed controller on and off remotely and leave everything else to work as was. 

Help would be much appreciated. 
 

Edited 3 March, 20251 yr by Morph