Fast blinking turn signal, brakes show dash night lights?

Ever since my car got into a small fender bender *i think 20 mph into a trucks bed* a string of things are happening. My right turn blinker acts normally unless the brake is applied. This does not continue into the hazard flashing. Furthermore, the dashboard lights that come on when my headlights are turned on are no longer visible, unless the brake is pushed down. They also have gotten much more dim. I was advised to replace the back right blinker assembly, which did not improve the situation. What is likely causing this issue, or where should I check next? How hard is it to do usually?