This sounds like either a defrost timer has gone bad,or the heater coils are not functioning.
I will need the make and model number of your unit to be sure.
Ok does your unit look like any of these?
Ok what I have done is upload the service manual for your unit to rapidshare.com for your retrival.
It has all the diagnostic proceedures for your unit and will help you to locate the problem.
If you have any questionsd please feel free to post them her, and I will answer them as soon as possible.
To download this file:
Click on this link
On the first page scroll down to the bottom and select "FREE"
On the next page enter the letters in the box and select "download"
Save the file to your hard drive and open it with a .pdf reader. I recommend FoxIt reader. (foxit.com) Its smaller than adobe and no spyware.
If this answer satisfies your question please click on the accept button. If it does not, please tell me so. You are not expected to accept any answer that you are not happy with. I do expect you to let me know if you are not satisfied, and what I can do to put a smile on your face.
Thank you for using Just Answer. Please tell someone about us.Best regards; The Home SmithyAfter you have accepted it is important that you leave positive feedback.
It should not be asking you to pay for anything.
Click on the link and scroll all the way to the biottom. There are two colums. One is for you to get a premium account. The other has the word FREE at the bottom. Click on that word.
The next page you will need to type the letters into the box next to them. Then click on download.
Let me know if you still have any problens