Driving down the road with my Mrs. having a casual discussion (the sound system was turned off). Noticed acrid smell of burning electrical. Unlike other reports, I didn't hear popping or crackling. Rear passenger compartment filled with gray smoke.

We bailed out of the car thinking vehicle was on fire. Extremely lucky that we didn't crash trying to get to a safe spot to pullover.

Right rear door had smoke coming from the door latch and window seal. I was standing by waiting on flames... after 10 minutes, the smoke stopped. Flames never appeared.

Cautiously drove E-550 to nearest dealership. Was told that rear speaker likely shorted out... dealer claimed it may be related to hot weather (115 degrees that day).

Luckily, I have a CPO extended warranty. I am torn as to having the dealer inspect all other speakers... can't believe there's no recall campaign on this potential safety issue.

Update from Aug 24, 2020: Filed under accessories...probably should have been filed under Electrical.