Fluence brake lights not working

I had a similar problem with my Fluence. Do you perhaps have a trailer hitch? Because in my case, the problem was with corroded contacts at the trailer hitch connector. Maybe check there first. You did not mention a trailer hitch. have you checked the light bulbs?

That's interesting about the trailer hitch. Yes I have one, but I recently installed it, it is a brand new one. I haven't towed anything with it yet. What kind of corrosion did you find back there? And how did you fix it. The bulbs are OK

I cleaned the contacts at the trailer hitch connector with contact cleaner. Then I applied some contact grease on them. Have you re-checked all the connections of the new installed trailer hitch? Maybe a cable is not correctly seated in the connector. You might also want to check the wiring harness on the trailer hitch. If you are unsure, take it to a workshop. They can diagnose the problem quickly.

Thank you for pointing me in the right direction! It turned out that the new trailer hitch installation was indeed the culprit. During the install, the installer probably damaged the brake light switch. The guy from the workshop told me I must have kicked the switch while installing the hitch. He reseated the switch, cleared the error and now everything is working perfectly again. Cost me absolutely nothing - thankfully!