I have a problem with my left brake light trailor wiring not working. It works when it wants to

It seems to work until I use the left blinker and then no brake light. I can get it work again if I tap on the interior drivers side fuse panel. I noticed there is a large flasher modual in that back of that panel, behind where stop and turn signal fuses are for the trailor lights. I am wondering if I may need to replace that flasher module or if there is something else wrong.