If you do please help me with this one. I am building a street rod and I am using a 80's column where the turn signals, brakes and taillights were on or partially on individual bulbs. However I am using single taillights on the rod with dual element single bulbs (1157). There is a common way of doing this to get brakes and turn signals to work together on one of the filaments by using a tail light controller from the RV - trailer industry. It lets you hook a single tail light trailer to a multi light truck. I am having trouble getting mine to work right. Here is the question - late 60's RR, GTX, barracuda all had single bulb dual element tail lights for stop turn and tail. In the era of no solid state trailer controllers how did the factory make that work???