87 190e heater switch problem

[bb190e]

the heater quit blowing air, every now and then the fan would kick on, just for a second,
so i replace the fan switch,
still no change , while i had the center console apart i found that on the heater control box that one (of the the many wires) that going in to the plugs that go in this box had two wires that are togather were not, so resolder them, plug every thing back togather, the fan still dosen't work .
if i take one of the wire that are hook in to the that plug and cross it over to another wires the fan kick on , only at a high speed.so i replace the control box with another. and if you push any control button nothing changes.,is there a relay that in need to replace and where is it?? don't know where to look..