what is the piece that bolts onto the heater box that has two black wires? one goes into the car with the vacuum gormet and the other goes?????? any one know?
Do you have a picture? It sounds like its the blower moter relay wires. These adjust the speed of the motor.
There is a resistor down there that uses the moving air in the plenum to keep itself cool. One wire should go to the blower motor and the other goes into the harness and makes its way to the switch. If that is what you are looking at ...........