I have a 93 LX 2.3L and the blower motor for a/c-heater only works on low no matter what position the fan speed nob is set to. I've checked the resistor, it works fine. Used jumper wires on motor, it goes full speed that way. Only thing i can think of is is either a bad ground or is the speed selector nob. Any one have an idea? Or dealt with same problem?