In the Buddy Club instructions that come with the tail lights it claims that 2017+ cars don't need to install the provided LED relay switch.
I installed the tail lights on my 2017 brz and the sequential turn signal mode doesn't work. But the normal non-sequential mode works fine.
Here is a video of what the sequential mode turned on looks like with the factory denso relay switch installed.
https://imgur.com/Q5W4ctN
I contacted the shop that sold me the tail lights to see what sort of feedback they are getting from other 2017+ customers.
Their reply stated that 2017+ needed the buddy club relay switch installed and the sequential function would only when the hazards are activated but not when using the turn signal.
So I installed the provided buddy club LED relay switch and the turn signal does not function at all whether in sequential mode or normal mode.
After some hunting a found a guy in Korea that showed that both turn signal and hazard sequential functions should work at the same time on a 2017+ car.
Here is a video showing the sequential function working for turn signals and hazard mode.
https://imgur.com/mVNoPZy
So what exactly needs to be done to get the sequential function to perform normally?