I am adding a function to the rear Turn Signals on my motorcycle (12vDC negative ground system). Turn Signals have 1157 incandescent bulbs - they have two filaments and three wires: ground, hot to running light, and hot to flasher. I want my Turn Signals to ALSO act as Brake Lights. So all I have to do is add a wire from the Brake Light to the hot flasher wire of my Turn Signal. Except, of course, that there are two Turn Signals. So if I connect wires to both, my Turn Signals will no longer operate independently (because they are both connected to the Brake Light). So I figure a Diode will prevent current from one Turn Signal passing across the brake light to the other Turn Signal. Of course, I will need two diodes - one on each Turn Signal. So I need a Diode that will live happily in a 12vDC circuit (actual voltage varies from 12 to 15). The 1157 incandescent bulbs are 28 watts or (approximately) 2.33 amps. So I want a diode that will allow 2.33+ amps to flow through one way and prevent current in a 12-15 vDC circuit from flowing the other way. I have found this diode at Radio Shack for $1.49 for two: 3A Barrel Diodes, Model: 276-1141 | Catalog #: 276-1141 Diodes contain 200A surge. Peak Inverse Voltage (PIV) is 50. Package of 2. It says nothing about 12vDC, but I think it means 3 amps can pass thru with no problem. And that the diode will not let current pass the other direction up to 50 volts of pressure. Am I reading this correctly?? Next is a tricky question mixing theory and practice. It seems that many years ago the auto industry wired cars under the mistaken believe that electrons move from Positive to Negative. So they designed cars as Negative Ground Systems. Of course, we now know that electrons really flow from Negative to Positive - however - the auto industry never changed their system, because it works. Motorcycles are the same. So if I solder a Diode into a Negative Ground System - which way do I point it???