I got the intergrated taillight from clearalternatives and I've plugged the factory harness into. The running and brake lights work. However, when I connect the yellow wires to the positive on the turn signals, I can't get the turn signals to work. Any help would be appreciated.

 

Have you tried a heavy duty flasher? You did not say the lights, 'DO come on' and that is where they just light up and hang without flashing. So, the HD type flasher has the push to force the relay to wink.