Heater\Ac dail only works on 4 but doesn't get cold?
If the AC does not work it may be low on Freon. Have it leaked checked.
Why does it work only on 4 but does get cold just had it service about 6 mos ago?
I think you are saying the A/C works but the fan blows only on 4. If that is the case, then the problem is probably the blower motor resistor is burned out. It's that resistor that allows speeds 1, 2, and 3. The fourth speed does not rely on the resistor at all. Check it out and see.
Fan only works on high is a bad blower motor resistor.
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