I am installing a 72vdc to 12vdc voltage reducer in my off road electric cart (golf cart on steroids) to run some LED light bars and a horn. The input of the reducer is constant 72vdc direct from the battery pack (6 12v batteries in series). There is a "control " wire on the reducer that is used to turn the output on and off. It is usually wired to switched power at the key switch and is also 72vdc. The key switch on my cart is 4 position switch; OFF-REVERSE-NUETRAL-FORWARD. I need output from the converter in both Reverse and Forward. I can tap into the key switch Reverse and Forward wires to supply the Control input of the Reducer 72vdc when the switch is in either of those positions. What type of diode can I use on on both the Forward and Reverse wires at the reducer to keep the Forward and Reverse voltages isolated?