For later models with higher amperage alternator
New voltage regulator to fit the following 201 and 124 models listed below from 1990 to 1995. No instructions included but not difficult to replace.
Late 201 and 124 Chassis Early 140 Chassis Voltage Regulator
$30.75
SKU:
ELT-COMLVR 
Product Details
Fits the following
1992 and 1993 190E 2.3 ONLY (Does NOT fit 2.6 models!)
1990 to 1995
300CE, 300E, 300SD, 300TE, 400E ,500E, E300D, E320, e420, S350 (Does NOT fit 4 matic)