I just installed a backup camera on my motor home , which is triggered by the reverse light wire. I would like to add a switch to the circuit so while I'm driving or just to be able to turn on the backup camera (using it as a rear-view mirror) without putting the vehicle in reverse. I probably need to add 1 diode to the backup light wire to prevent the backup lights from coming on when I turn on the camera using the additional switch (bypass). And will I need an additional diode to be installed on the bypass switch to prevent 12 volts traveling back to the manual switch as well? If I'm on the right track about all this, what size diode or diodes will I need?