1989 bmw 325i - there's a dial near the handbrake that reads s-e-321. What does this do

freakin' dude....your avatar is frightening....turn the knob and see what happens.....perhaps a PM to Robert Charlson, Matt Mankinen, or Michael Brannan could sus this one out fer ye~

I have a very stock 1989 325i convertible with an auto trans. I don't have a dial. That sounds like a custom aftermarket deal. Maybe you can take it by a dealer and someone can help you identify it.

Coy325i, you stated your car is very stock. This knob was an upgrade for 3 series and standard on 6 and 7 series with automatic transmissions.

Cool. What's it do?

E= economy, your car will shift normally S= sport your car will shift up later and down sooner, it'll also hold gears longer so when you ease off the accelerator it won't immediately up shift. 321= it eliminates the 4th gear