blower regulator
 

had intermitant blower motor found broken wire on right side of climate control switch 82 380sl 107 soldered connection.
remove and blew clean climate control switch no evidence of breaks in solder cleaned and replaced. blower motor works with 12 volts applied. where do i find the blower regulator and is there anyway of testing it to see if it the problem.
if i place the left harness to the climate control switch and press the defrost button the blower works but only in high and with out help from the blower switches
please help?