Since I purchased this car in October, I have spent $1000 fixing it up a little bit. I flat out don't really have time to work on my cars myself at this moment, so I have had to try and find a trustworthy mechanic. I don't feel like I have found the right one yet though. The heater core was just replaced, but my defrost still doesn't work. Now that winter is almost over, it's not as important, but still needs to be fixed. My ac works a little bit, and the defrost works a little bit when ac is on full blast. That's probably a blower motor, right?

 

There are a few things that could be wrong. If it sounds like the fan is blowing at full speed, but you aren't getting much air out of the defroster vents, it may be a bad mode control motor. The logicon is also a possilble culprit.
If you have a bad mode control motor, you won't be able to switch the air from feet to vent to defrost very well. Try seeing if you get good air flow at each one of those positions.