The left brake does not work when light is on?

Thanks for the detailed response. I pulled and checked the 4 suggested fuses with a multi-meter, and they are all good.

I noticed in the wiring diagram that the license plate light is included in this circuit. I checked those and the one on the left is burned out. This is on the same side as the brake light with which I’m having issues. I haven’t replaced it yet but will do so later today. Do you think that might have something do with the failure?

I found the issue. When I went to replace the burned out left-side license plate bulb, I found the entire socket and housing to be wet and dirty. I cleaned and dried everything and replaced the bulb. Checked voltages and functionality before buttoning everything up.

All rear lights are now functioning normally. Thanks for sending the wiring diagram. It was very helpful in pointing me at the solution.