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Internet diagnostics are sometimes dicey, and when you say you replaced all these parts I am led to believe that would be brake light switch, turn signal relays, all related fuses etc.
I would look for bad grounds...run a voltage check at the light sockets and see if you get a reading with the brake pedal deppressed...should be at least 11+ volts.
If you don't, you have a ground issue. There are 2 ground straps un at the front of the bed that ground the bed to the frame...these are uninsulated so over time they fray and corrode away. There should also be a ground from your wiring harness or trailer plug if you have one to the frame above the spare. If it appears rusted or corroded you need to remove, clean and reinstall. BTW you can help stop future issues by painting or applying liquid rubber over the new connection
There is also a lighting harness ground under the battery tray...Stupit Dodge...right where all the battery acid fumes fall. I've had to clean and repaint mine twice. Actually some Rams have two ground studs under there.
Keep doing voltage checks until things start working again.
