It is thermosted!
I did replace the heater coil in the windsheild washer fluid reservoir (got it from Phil at Fast Lane ~ 105 plus couple of rubber seals (grommet) for the tubing). The coil is in three parts actually, two tubings one is coiled, both tubings attach to a thermostat. My washer temperature now is ~34C or ~93F.
Car 92 400E 167K mi. W124 M119