wiring check

I cannot answer for a 72 Dart, but the brake lights on a 69 Barracuda go through the turn signal switch. After a complete restoration about 9 years ago, I was going to take the car for a test drive, but there were no brake lights or turn signals. After hours of testing and looking at a wire diagrams, I found that brake lights and turn signals both went through the turn signal switch. I replaced the turn signal cancelling cam (TSCC) with a new (turned out to be garbage) part. On the back side of the TSCC, there are four metal prongs. or wires, that make contact with different copper nodes on the turn signal switch depending on the position of the turn signal lever. It turned out that those prongs/wires were not making contact with the nodes. So I bent each wire down (away from the TSCC) so they could make contact with the nodes. Everything was fine after that.