Do you have the ability to pull the RCM out of its box, remove the case from it and study the condition of the contacts inside it. Then with it laying on top of the the case,put the plugs back on it and see if the relays are working correctly when you try and start the car?
There are two solenoid in the RCM that can fail, the fuel pump and another.
Can you hear the fuel pump when you just turn the key to the run position?