AC not working

I have a 1996 Grand Voyegeur SE (JUNK). My AC went out this summer, I had the compressor changed, and refield the coolant. I was told that my evaparator was bad. If so can I change it and how? This isn't the first thing that went bad with this. Only two doors unlock with the automatic locks, passenger side lock/unlock button doesn't work. wiper light buttons flash, transmisson slips, radio goes in and out frequently, I have put two starters in, oxygen sensor, check engine light flashes on and off. I will never have another. If you can help me out thanks, I understand if you can't.