Hi,
My 2008 Volvo S60 2.5T has a backside electronic issue.
When I turn on the left turn signal at night with the headlight on, the backside lights (turn signal light, brake light, night lights, backup lights and even parking sensors) are acting weirdly like the following video.
https://www.youtube.com/watch?v=W1tMg8nGOm0&feature=youtu.be
This symptom does not develops when the headlights are off. And right turn signal works fine even at night. Only the left turn signal is the problem !!
I can hear some clicking relay sound at the rear relay box when this symptom is developed. (You can hear the sound at the video if you pay attention.)

We don't have Volvo dealership around my place and I replaced the REM as the local mechanic recommended but the symptom is not fixed.
I can see only the intermittent rear parking sensor failure message at the dashboard when the symptom is developed .
I have no chance to examine the error code with the genuine Volvo scanner, but local mechanic says no error code was seen with his scanner.

My place is isolated island and very difficult to bring the car to the Volvo service facility.
I would appreciate any advice or suggestion.
Thanks in advance.

Wonki..