Do aftermarket systems exist that can allow me to add blind spot warnings to my side mirrors? I recently drove a Honda Ridgeline from L.A. to S.F. and decided that I like the feature. It lights up a warning light in the side mirror if you turn on the turn signal and try to merge when another car is in your blind spot as a sort of safety device. I never want devices that take over for me (ABS, lane holding, autobraking etc.) but a well timed warning indicator is always welcome...

2009 Infiniti G37x

 

There are plenty of kits that will emulate the "Blind Spot Warning" tech but none will integrate into the existing mirror glass/ housing like more modern cars have. For that, at a minimum, you would need mirrors, sonar sensors, control module(s) and a ton of wiring. Nissan, and most aftermarket kits, just add a LED to the interior corner support (near where the tweeter is) which lights up when triggered. Pic is for 2019 Q60:


Now whether the aftermarket kits include turn signal integration I do not know. It seems most of them just use a simple sonar sensor and related wiring.

Just research "Blind Spot Warning" kits and tons will pop up. Perhaps other forum members will have other suggestions...