Automatic transmission (AT), block diagram - GF27.10-P-0001-20AHS
The BAS release switch (A7/7s1) on Model 221 is replaced as of 2.6.09 and on model 216 as of 1.9.10 by the brake light switch (S9/1). With code (233) DISTRONIC PLUS and code (239) ART Plus Light, the BAS release switch is still used.
Courtesy of MERCEDES-BENZ USA