I have a 93 chevy the blower blows on low and high at the same speed(high)but doesn't blow on medium I changed the resistor still does it the switch clicks on all setting but no fan on med. I haven't changed the relays could this be the problem?and what relay is the fan is it all three?the fan relay if fine clicks everytime i change speeds bt no voltage at medium and same voltage at high and low any ideas

I'm not 100% familiar with them, but if the 93's have the same switch as my old 81, there are four distinct separate contacts at the switch (power, L, M, H). And they aren't the most sturdy of things. I ended up bypassing min as the switch actually fell apart (one of the contact assemblies actually broke free from the switch and was still plugged into the socket).

Check the plug on the back of the switch. There should be four wires. None of them are ground, so no chance of blowing something up. Take a short piece of wire and try poking it into the hot lead and then crossing it over to the other wires. One wire for each speed. If the fan operates on the different speeds this way, you know it's the switch. If you still don't get medium speed, then you know it's the resistor pack.

[EDIT] Just saw you changed the resistor out. I would be pretty sure it's the switch. Try it out. The hardest part about the whole thing is getting the dash panel out (unless the plug on the switch is corroded in place like mine was).