If I turn the fan speed selector to 1 or 2, the blower motor does not kick in but3 and 4 work just fine. I have already swapped the switch from one at the wreckers and it also does the same thing. Either the one I got also has the same problem, or it is not the switch. Any ideas?

91 Civic SI HB

 

Might check out blower motor RESISTOR. Track wire from blower motor up to where it connects to resistor. Remove resistor (usually two screws) pull out of housing and have tested

 

Yes it's usually the resistor. Remove the glove box and you'll see the resistor mounted in the top of the air duct leaving the fan. Unplug it; it should have a four wire plug. There should be only a few ohms resistance between any two terminals. If one or more terminals are open, it is bad.