So my A/C works as well as my heater, but the only problem is that it only works on 3&4. If i put it on 1&2 it doesnt work. Would could be the problem here? How can i fix it or how much would it be to get fixed?

 

Sounds like a problem with your blower resistors.

There are combinations of resistors for each of your blower settings. The most resistance is on the 1st speed. The least resistance is on the 4th speed. Each speed has less resistance. Each speed uses a different circuit, or path, of electricity flow. If the resistors for the 1st and 2nd speed are broken, then your fan won't work.