need to seperate signal flash and brake

Hello, I recently purchased the a Led light bar for the back of my truck from Plasmaglow (http://www.plasmaglow.com/products_trucks.php) when wiring it up i have come across a problem. I have a 2000 GMC Sonoma, same as the Chevy S10, and there are 3 wires that come out of the brake/tail/running light in the back, one is ground, the other is for one filament that is the running lights, and the 3rd is for the blinking turn, and brake. The problem i am having, is that when wired correctly, the turn signals of the new Led light come on with the brake, and the brake lights come on when the turn signals are activated. I guess I need some sort of a signal splitter that can turn the one wire going to the filament that controls the blinking and braking into 2 separate wires so this can be wired correctly. Please let me know if anything like this exists, and where to find it.