How to Diode to Prevent Feed Back?

Well, I have a Jeep Grand Cherokee SRT8 that does not come with rear fogs install. I working on a T-Harness to wire the rear fog lights from the tail lights. when I connect the harness, both the tail light and the rear fog light turn on but both come on like if I was pressing the brakes. My question is how and where can I still a diode to prevent feed back? If anyone have a diagram it would help me a lot. Thanks for any help..S1l3nt

These are the pictures on how I want to connect the t harness onto the tail lights,Thanks for any help...LuisS1l3nt

That harness is simply paralleling the new socket with the other bulb.  I still have no idea when you want the fog lights to come on.  

I want to use the fog light as running light and also as a turn signal with the tail light. I saw some guy with it and when he hits the brakes both the tail lights and the fog lights come on to full lit.. But he doesn't wanna help me because he is selling the harness and I want to do own without paying for it. S1l3nt

lam13 wrote: I want to use the fog light as running light and also as a turn signal with the tail light. I saw some guy with it and when he hits the brakes both the tail lights and the fog lights come on to full lit.. But he doesn't wanna help me because he is selling the harness and I want to do own without paying for it.

  Is this legal?

I don't see why this can be ilegal, I just want to add an extra break light and turn signal light.S1l3nt

White light to rear is illegal in i think all states, thats why if someone takes out an amber turn signal bulb in the back and replaces it with just a regular bulb he gets pulled over and given a fix it ticket.~*Ben*~

That's not a white light, its a LED RED LIGHT, that I want to use as a running light in the rear FOG LIGHT HOUSINGS... LUISS1l3nt

How much is the guy selling the harness for?Kevin Pierson