First of all, excuse my electrical ignorance. I'm not sure how to hook it up. You say it doesn't go in line? If it isn't between the clutch and the item it must protect, how does that work? As I understand it, you want me to take out the diode, splice those two wires that attached to it and another wire with a spade terminal together.
Then I must make up a wire from ground with a spade terminal on it.
The terminal from the clutch wire goes to the "notched" corner of the bridge, and the ground wire goes to an adjacent terminal(doesn't it matter which one?).

I still don't see how this interrupts the spike back to the control system.