Couldn't you just unplug the one wire on the lights, I don't know the color since I'm not at home at the moment to look.
I put after market lights on my TW and they were only 2 wire lights, so I didn't plug in the third wire for the running lights. One is the ground, the other is constant power and the last is the one coming from the turnsignal relay to blink. (Please some one correct me if I'm got it wrong)
Now my turnsignals only blink when the turn signal is on. I did this to try and cut down on power consumption so I could run with heated gloves a little safer.