The 190e had its heater by-passed. It is not too hard to do. You remove the cover over the wiper assembly, disconnect the hoses going into the heater core at the firewall and route a new hose along under the wiper.
Regarding cool; well yes. Regarding damp; just make sure the fresh air in some amount continues to travel through the cabon of the car.
On other and unsual approach is to disconnect the tubes at the heater core and try replacing just the O-rings. Often though it is the core itself. Or, you could run a tube through the fire wall and across under the dash and backout again. Yes, it is crude, but you would have some heat or always have heat.
'03 E320 Wagon-Sold
'95 E320 Wagon-Went to Ex
'93 190E 2.6-Wrecked
'91 300E-Went to Ex
'65 911 Coupe (#302580)