Im not sure but in the w124 e320 the start harness connects to the blower control which may not work to control the blower if its failed..but the car will not start without this blower controller installed. Ive had it out and the ignition system is dead wthout it..

And the blower system is automatically controlled with several inputs from the climate control including heat/ac/ and will come on high or turn off automatically when called for by given conditions..goes from low to high and off without changing the buttons..as temperatures change..