To start with change the trans fluid! If the fluid in the pan is burnt service only the pan, if the fluid is somewhat clean then also drain the converter. You will need 7+ liters of ONLY the factory fluid. Also check the electrical connector at the front of the trans for fluid leakage, replace if there is any fluid in it.
The most common problem with erratic blower operation is the electronic blower control on the motor. Check for command voltage changes from the A/C pushbutton panel. That car has a "micro" dust-filter, make sure that it has been changed. Both are under the right under-dash panel.
The only reason MB & all other European car makers don't recomend fluid changes like they used to IS; they have to pay for recycling costs for all recommended fluid replacements.
HAS nothing to do with engineering changes at all.
MERCEDES Benz Master Guild Technician (6 TIMES)
ASE Master Technician
Mercedes Benz Star Technician (2 times)
44 years foreign automotive repair
27 Years M.B. Shop foreman (dealer)
MB technical information Specialist (15 years)
190E 2.3 16V ITS SCCA race car (sold)
1986 190E 2.3 16V 2.5 (sold)