61 valiant turn signals ??

The turn signal switch in the steering column has a bunch of wires. 2 for the front 2 turn signals and 2 more for the rear 2 signals. This is so the rear can be shared with brake lamps. 4 wires to 4 lamps. It's not uncommon to loose one of the 4 in a failed signal switch.
In a different post you mentioned a 3rd add on brake lamp. You'll need to finger out how/where that was tied in. We can't know if it was wired properly. I'll assume the OEM wires were cut and spliced somewhere.