I have an '89 Skylark custom 4 door, L4 2.5l, with about 190K on it. My blower fan only seems to work in "high", no medium or low speeds. I replaced the climate control module with one I found at a salvage yard and got the same result. Is my problem with the blower resistor and if so, exactly where is it located? Thanks

It sounds like the resistor is your problem. I don't know where it is. But they are usually by the blower motor

you can find it by looking at the duct, most are in the air stream so you will see heavy wires going into the outside of your air duct