Brake/ rear signal lights not working

You have replaced the bulbs, and I am assuming the bulbs were the correct ones (dual filment...probably...#3457...). Next, the modules in this vehicle that control lighting do provide fault codes for the circuits, so you can scan for codes if you have access to a scan tool. If you have no code information, here is some theory on how the system works. Your brake light switch on your brake pedal sends a signal through wiring, and through some splices and wiring connectors, independently continues the signal to the middle brake light and sends the same signal to the Smart Junction Box (SJB). From the SJB, it sends direction independently to the left and right rear bulbs. Since your concern is for both left and right rear bulbs at the same time, you would probably have a concern in the SJB itself (which is a programmable module...check for water intrustion maybe causing a short?), or the wiring from the SJB through the dash itself. Would be a tough diagnosis to trace the wiring behind the dash. Usually it is not that complicated. Check for power first at the brake light sockets just to ensure the bulbs are not initially at fault. Good luck!

Not sure what the problem is if all the fuses are good,but, an easy way to find out if you've got juice to the lights is: Have a friend push down on the brake pedal while using a DMM meter check to see if your getting 12V or more at the bulbs contact points