Too much going on here.
You need a wiring diagram.
Mymopar.com
classiccarwiring.com
Then you need to understand that the power for the brakes and the headlights DO NOT go thru a fuse, they are hot all the time.
The instrument panel and map lights have nothing to do with the brake lights directly.
Your problem could be the turn signal switch, connector or wiring
Could be bulbs
Could be wiring
Could be grounds