Pin 30 is power and 87 is the normally open side of the switch, you jumper those two pins. If you mess up and go to 'control side' ground pin 85 you will fry the computer. Pin 86 is power for the control side of the relay. I start by checking for power to both the load (30) and coil (86) then I check the operation of the relay, I use the horn circuit and swap relays around and honk the horn. The diagram from the relay circuit and pins is right on the relay.