rear trail / extra reverse lights

I'm sorry I have searched and searched through post, some are like what I'm trying to do. This is what I am trying to do is, I have placed two small fag lamp on the rear bumper of my Jeep Wrangler, I want them to turn on with the reverse lights and turn on with a switch. When I turn on the switch, I don't want to back feed the reverse lights and have them come on. I have found a wiring diagram for what I'm doing, BUT, it does not tell me what diode to use, just an Isolation Diode. Can I use a 1n4003 or does it have to be a 1n4001 or maybe something else?In advance thank you for your time...

1N4003 is safer than a 4001. Basicly you're looking at peak inverse values, i.e. the average car will nominally be 24-29volts. As the numbers of the diodes increase, so these values increase. 

Thank you, I will give the 4003's a try.

Well so far so good, used the 1n4003 diodes wired everything just like the diagram and everything works....